What I expected to happen was...:
game running as smooth as in previous versions when i summon bigger amount of particles

What actually happened was...:
game got really laggy, my TPS and FPS dropped  as soon as i started generating particles

Steps to Reproduce:
1. Make a datapack which contains 2800 particle summon commands
2. Run it on 1.16.5 and any version above 1.17
3. Compare performance

I attached 3 files which I ran at the sime time using repeat command blocks