Some small nitpicks: you don't have to add them if you don't think its valid.

1. Rearrange the help screen with the sync notifications first, then the file transfer, the remote control. I would hazard a guess that thats what people want the most. Again not sure so feel free to use your discretion.
2. Googles HIG guidlines state that you shouldn't really display a screen showing ui, rather you should overlay disrections over the UI. https://material.io/design/communication/onboarding.html#top-user-benefits-model. However I also don't know how many people actually follow this.

Breadcrumbs are kept in place so that user doesn't feel jared. That throughout the entire application the look and feel is the same. In Dolphin, Konsole, and most of the KDE applications the about info is in a new dialog for this very reason. However if that's not an option then at least keep the breadcrumbs.

I had a couple of comments about this type of implementation and posted it in a PR discussion but will re post it here so we can discuss it.

The tradional way to open up a bluetooth connection and adding the device as a source. Thats the way windows "Your Phone" does it, that's why can't connect multiple bluetooth devices to your pc as once.

So maybe not for kde connect but another kde app in general. I have found that this is needed as most services try to get you to store both passwords and your OTP for the same service which kinda of defeats the purpose of two factor authentication.