Baloo uses an implementation with quadratic complexity when removing items from lists, e.g.:

https://phabricator.kde.org/source/baloo/browse/master/src/file/fileindexscheduler.cpp;b08e011ac69ee4cd5a46f434d47254049be3fc8e$145

https://phabricator.kde.org/source/baloo/browse/master/src/file/pendingfilequeue.cpp;b08e011ac69ee4cd5a46f434d47254049be3fc8e$61

O(m*n) m: removed items, n: items in list

use std::erase(std::remove_if(begin(), end(), predicate))

see https://git.qt.io/consulting-usa/qtbase-xcb-rendering/commit/89034600939bbfe241ba3d6136abf7bb6961db52