X11 has XRender since ages. Now it has XCB and optimized setups.
And, OFC, composited Window Managers avoiding raw X11 calls with X11 extensions... since early 2000's.
Using X11 for any modern needs is an aberration.
Debian isn't made by a trillion-dollar company. Very few resources are allocated to testing it, worse yet, there's Redhat always breaking things ever since Gnome went to shit in 2011, which affects pretty much all DEs to some degree.
>Because half the GUI toolkits on Linux are either absolute pieces of shit (GTK lol) or simply not enough.
Last time I checked even GTK manages to NOT fuck up its widgets when resizing the window without requiring the developer to go through all the bullshit of LiveData and then a couple of years later also some new bullshit like Flow or whatever, until Google comes up with something yet more over-complicated.
Then there's also Qt which has even been ported to Android.
Despite some weird architecture choices (binders are some weird ass things to handle), the deep changes to Android make it a tolerable OS for mobile purposes. Using X11? Sure, I love display servers that choke on high DPI and cannot do half the things modern compositors do efficiently.
LiveData is not part of the UI framework but merely a tool to provide updates to be listened to on the main thread. It's also half deprecated and you should probably be using flows instead. Why is it here? Because half the GUI toolkits on Linux are either absolute pieces of shit (GTK lol) or simply not enough.