it just gets stuck like this, completely unresponsive.

Computer specs:
OS: Linux Mint 20.1
KERNEL: 5.4.0-71-generic
CPU: AMD Ryzen 9 5950X 16-Core
GPU: Radeon RX 580
GPU DRIVER: 4.6 Mesa 20.2.6
RAM: 32 GB

(copied from proton DB, not sure if the drivers matter)

i would have said this is a duplicate of #19, but you're on mint...

is that a CubicWorldGen world? if so, are you using heightmap mode? it looks like it.

the mods enabled

the forge version

EDIT: whether i enable optifine or not its the same result.

you still didn't answer either of my questions...

ah yes sorry, i'm pretty sure that that world is being generated with cubicworldgen but again the result is the same whether i use vanilla or not.
if you mean the render mode, it's using the voxel mode for rendering.

everything is basically on default, whatever i try it leads to the same result

It appears i had not uninstalled the propriety AMD gpu drivers that i had installed for 🤷 reason, works fine now, sorry for bothering everyone.

It appears i had not uninstalled the propriety AMD gpu drivers

well, that is interesting. i'll update #19 now that i know the issue is with the AMD drivers, but not necessarily specific to windows.