Moved from iOS to Android recently and the first thing I did was install a new FOSS launcher and Articons. The Settings menu and sharesheet still show the original app icons. App theming choices are much more limited, just hope they respect your system theme and font scaling, which the latter definitely can break layouts rendering some apps unusable.

I don't really have a point with all of this; I just think there's a middleground that can be met to let users modify whatever they'd like, and straying from the Happy Path that devs test for could show a warning or a way to let them choose to revert certain system defaults for your app.