THINGS THAT MADE THE CONCLUSION

1. Clearing Cache returns all the fps from 1.16.
2. Cache is up to 3GB. (at my record)
3. Playing minecraft for longer periods of time decreases performance. And increases cache
4. Dramatically decrasing lag when clearing cache

EXPECTED ON BUG FIX

1. 40-60fps
2. Cache will be properly managed automatically
3. Cache will have a setting(e.g. max cache 64MB-1024)

REPRODUCTION

Notice##: Do this on a low end device. You may not notice the bug on high end systems. I recommend using android for the ability to clear cache while minecraft is running.

1. Play on any world/server with many players.
2. Load as many skins, profile picture as possible.
3. Be busy loading textures, skins, marketplace thumbnails and profile pictures for atleast 45 minutes.
4. Look and observe your fps, responsiveness, lag
5. Check your cache (do not close minecraft)
6. Clear Cache(do not close minecraft)##Clear Cache while minecraft is running
7. Open minecraft(you might see pink glitch but that's normal)
8. Look and observe your performance again
9. Compare

Why am I setting this up to multiple devices:

1. I have tested this in Windows 10. It seems to load the marketplace images slow at first (my internet is slow 1mbps), then after relaunching the game, loading up the marketplace for the second time was fast.
2. IOS still unconfimed but I saw this video from youtube it may help https://youtu.be/CjCLtI_k2dI
3. I don't have a console
4. Android Confirmed

Alternate title for this bug

1. Minecraft indefinitely loading cache.
2. minecraft does not unload unnecessary cache.
3. Cache gets overwhelmed on low end devices