When I had my last Android phone (KitKat 4.4), best tip for increasing UI snappiness was reducing (or disabling) system animations. I still miss this option on most modern OSes, shells, apps, and websites.
It's very rare that animation is not blocking further user actions. No surprise animations are tricky to program - they're very async in nature. Designing animation system that doesn't leak into the rest of application logic code is a no simple feat.
Tangentially related, games added various menu transition animations on purpose, to disable user input while loading resources (from hdd or network).
Idea being that for user it is less frustrating to wait for animation to end, than to see some hourglass/waiting indication.
This still exists on modern Androids (thanks God!)
Even better: they moved it from developer options to accessibility options, which means that they treat it as a normal use case now
What is bad is that it still disables the animations for progress bars (the only place where the animation makes sense)