The MC-162253 bug, the core problem which this mod fixes, was fixed in 23w16a. This mod is no longer necessary as of 1.20.

The MC-162253 bug, the core problem which this mod fixes, will be fixed in 23w15a. This mod is no longer necessary for future versions.

but unfortunately, I also have this problem on 1.20

The only possibility for you to continue to have this issue is if you are on a low-end device or having a messed-up configuration. Try allocating more memory to the game.

The only possibility for you to continue to have this issue is if you are on a low-end device or having a messed-up configuration. Try allocating more memory to the game.

But I have a normal laptop with a discrete RX5500 graphics card and a Ryzen 7 4800H processor, and I allocate 8GB of RAM out of 16 for minecraft. Without this problem, I have a stable 300 fps in the single player world

What mods are you using? Sometimes mods can create performance issues.

That's weird. Also, you don't need Starlight as of 1.20 because Mojang rewrote the lighting engine to improve performance with very similar effects to Starlight. It's only being updated for servers and has no effect on the client.

I'm not sure why you are having these issues. Try looking into any mods related to chunk loading (like C2ME) and see if there are any similar issues reported. I also use C2ME and don't have these issues, so it might be something related to Farsight or another mod possibly.