This is generally a mix of MATE and GNOME, yes?
If I recall correctly, Ubuntu MATE sets it so that Home == Upper Left, End == Bottom Left, PgUp == Upper Right and PgDown == Bottom Right, because of their layout on a typical keyboard. The only issue I see with this is the fact that some more compact keyboards such as those of laptops can come with these four keys above the numpad, but since corners are more unusual than Right and Left, it could be used.
Home and End are however set up so that they fill the gap caused by the need to use Meta+Up for maximize and Meta+Down for minimize, which comes from GNOME. I do agree that these two, namely maximize and minimize, are very useful, but I'd like to finish verifying other DEs first just to be sure that this is used in more environments, because it introduces some changes to consistency with other keyboard shortcuts, especially navigation keyboard shortcuts.
I find this a very thought out layout, but ultimately it depends on whether we follow GNOME's Up for maximize and Down for minimize, and it also depends on which modifiers we will use. I'd say that your suggestion would pretty much be a given if we choose to do that, but that would be me particularly, I'd also like to hear others' opinions on this.

Keep in mind that laptops without numberpads and a 2x3 grid of navigation keys are not some niche use case anymore, so any layout that makes sense primarily on a full-sized 104-key keyboard may not be the best choice.

In T10567#208723, @thiagosueto wrote:

This is generally a mix of MATE and GNOME, yes?

It's not intended to be but yea, there may be some overlap.

In T10567#208723, @thiagosueto wrote:

If I recall correctly, Ubuntu MATE sets it so that Home == Upper Left, End == Bottom Left, PgUp == Upper Right and PgDown == Bottom Right, because of their layout on a typical keyboard. The only issue I see with this is the fact that some more compact keyboards such as those of laptops can come with these four keys above the numpad, but since corners are more unusual than Right and Left, it could be used.

I think the nonstandard keyboard issue is pretty much impossible to solve unless we can change shortcuts based on keyboard layout (is it possible to detect non standard keyboards?)

I have attached an image of a non-standard keyboard where there is no possible way to make the Quick Tile shortcuts make sense in a grid style like normal layout.

Home and End are however set up so that they fill the gap caused by the need to use Meta+Up for maximize and Meta+Down for minimize, which comes from GNOME. I do agree that these two, namely maximize and minimize, are very useful, but I'd like to finish verifying other DEs first just to be sure that this is used in more environments, because it introduces some changes to consistency with other keyboard shortcuts, especially navigation keyboard shortcuts.

I think it is understandable to verify other DE methods prior to implementing though I would like to mention that maximize and minimize are much more common than tiling so even if these are not used we need to find a simple method of implementing these shortcuts rather than the current shortcuts of Meta+PgUp & Meta+PgDwn as those are more likely to be placed behind a function key on laptops.

I find this a very thought out layout, but ultimately it depends on whether we follow GNOME's Up for maximize and Down for minimize, and it also depends on which modifiers we will use. I'd say that your suggestion would pretty much be a given if we choose to do that, but that would be me particularly, I'd also like to hear others' opinions on this.

Thank you and I agree that I would also like to hear more opinions on it. 👍

In T10567#208725, @ngraham wrote:

Keep in mind that laptops without numberpads and a 2x3 grid of navigation keys are not some niche use case anymore, so any layout that makes sense primarily on a full-sized 104-key keyboard may not be the best choice.

I think it is impossible to find a method that fits with every layout when considering laptops as they vary so much. Because of this, I think it is better to setup a structure that applies to the standard layout and let people with non-standard keyboards to go in and change the settings themselves to fit their layout.

Currently, for the most part Plasma already requires people to customize the shortcuts so not a ton would change in that regard especially taking into consideration the laptops that have keys behind function keys, it would be very unlikely someone would accidentally stumble upon the standard layout shortcuts in those cases.

I also think that Maixmize and Minimize a much more important than the current shortcuts of:
Window Quick Tile Top=Meta+Up
Window Quick Tile Bottom=Meta+Down

Alternatively, is it possible to make the shortcuts context aware? This would be the ideal structure if it is possible because if so this would use Meta+ arrow keys only.

Let's say you have a window that is in normal layout and you want to put it in a Top Left 1/4 placement, you would press Meta+Up (this would activate Window Quick Tile Top, the full horizontal top) and then press Meta+Left to move into the 1/4 placement.

In this same structure, you would maximize by pressing Meta+Up twice as it already knows it is in the horizontal placement after the first one. Same thing with down and twice.

This allows the shortcuts to only be arrow keys and lets you very quickly switch between the locations with very little hassle once the workflow is known.

For reference, I am pretty sure that Linux Mint's Cinnamon works this way

BTW since this was filed, things changed a lot upstream, so you now do the following by default:

Meta+left: tile left
Meta+right: tile right
Meta+up: tile to top
Meta+down: tile to bottom

Meta+up+left: tile to top left
Meta+up+right: tile to top right
Meta+down+left: tile to bottom left
Meta+down+right: tile to bottom right

It's exactly what Cinnamon does.

Maximize with Meta+up+up and Minimize with Meta+down+down are coming with https://invent.kde.org/plasma/kwin/-/merge_requests/81#note_72392, once I get off my butt to finish it.

Do you think there's anything left for Kubuntu to do here?

Does that mean that Meta+pgUp will no longer maximize the current window?

It's exactly what Cinnamon does.

I don't think it needs to double set each time. Once you activate the tiling it is aware at least thats how I remember it. Once you activate the tiling you can just do left and right rather then having to Meta+Up before the left and right each time. If KWin needs to sequence style for it to make sense then that is a reasonable solution as well. 👍

Does that mean that Meta+pgUp will no longer maximize the current window?

that is what I was suggesting as Meta+PageUp is an awkward inconsistent shortcut on many layouts and the maximize function deserves something more available reliable due to the importance of it in many people's workflow.

Meta+Alt+Up would be a reasonable solution for it though so that doesn't conflict with this tiling approach Nate mentioned.

In T10567#239171, @mparillo wrote:

Does that mean that Meta+pgUp will no longer maximize the current window?

No, it still will. There will be two ways to do it.

In T10567#239173, @michaeltunnell wrote:

It's exactly what Cinnamon does.

I don't think it needs to double set each time. Once you activate the tiling it is aware at least thats how I remember it. Once you activate the tiling you can just do left and right rather then having to Meta+Up before the left and right each time. If KWin needs to sequence style for it to make sense then that is a reasonable solution as well. 👍

That's exactly what it does, basically. Give it a try if you haven't used it yet. Hold down Meta and then hit the up arrow key and then right arrow key (within a second or two). In my experience it works nicely.