I know, I know, but Flappy Bird.
It won’t be long before you won’t be able to play it anymore. This is due to Flappy Bird being 32-bit, and support for 32-bit apps is ending.

For example, the Google Pixel 7 already blocks installation of 32-bit apps.
Also, the new SoC designs won’t inlude 32-bit support, which will be the hardware-dictated end of such apps.
Enjoy it while possible.

Anyway, my favorites are Bus Simulator: Ultimate and Truckers of Europe 3.
Though, you may find them boring.
If you do try them though, be ready for your phone to turn into portable cooker. The heat already killed one motherboard in my phone. The other one had different issue.
Yes, my phone already had 2 in-warranty motherboard replacements. Poco X3 Pro, what do I say. A pretty common issue.
Generally your phone will just slow down instead of cooking itself, but that doesn’t mean the heat should be ignored.