Any shaders for Potato PCs?

[VolteVaris]

My pc does run the game; but chugs at higher quality. Shows what I get for not cleaning my fans out.

Any mods that help keep the stunning visual impact even on the lowest settings? I'm a huge retro dude, but it doesn't capture as well.

[Ǵ̶͓̂͑lí̴̤̀̄́tcĥ̸]

I would look into Reshade. I use it for basically every game, the amount of things you can do with it is insane and it's easy to install with the standalone installer. Shader effects through an option called ColorMatrix or DPX for example can have some pretty awesome effects by changing the colors of everything (can completely change the feel of the game to be honest, like make the lava zone look like a blue plasma zone instead), plus the usual stuff like sharpness (increases sharpness of the textures, including normal maps), colorfulness/vibrance (saturation basically), its own versions of AA (FXAA and SMAA) which may or may not perform better than the game's AA, and so on. All of it is located in the same menu, you just download the shaders when you install it and check a list of the ones you want - you will see what I mean when you install it. It's easy.
https://reshade.me/
As for what each shader/setting does, check the first post of this link:
https://reshade.me/forum/general-discussion/4910-reshade-settings-install-guides

Some of Reshade's settings can have a performance impact - but you have pretty great control of them all and once you get good at messing with it, you can replace some game settings with the Reshade variant (like AA) and sometimes get better performance with the same visual quality - all depends. Just experiment.

Also if you have Nvidia Control Panel, you can go to Manage 3D Options and add Subnautica to that list, then scroll down to Power Management and set it to Prefer Maximum Performance. Might make a potato sound like a rocket ship and work a bit harder than it likes, fulltime, during play though so keep that in mind. Adaptive (instead of maximum) is also a good option if you don't want to overwork your PC.

[VolteVaris]

Pretty old PC, for all intents and purposes

[Cougarific]

"Shader for Low Settings" on Nexus:
https://www.nexusmods.com/subnautica/mods/10