>>403612012
Alright, you're right that reducing the resolution is the best way, but also reduces texture quality a bunch.
Also, atlas your textures and remove unused UV space from deleted meshes.
Tile normal maps and textures that use repeating patterns and make the resolution smaller
Matcaps don't need to be big at all, put them down to like 52px. Same with masks, they can often be pretty tiny resolutions.

I'm deviating here though, what I meant was the best way to have minimal quality loss is to mess with the compression settings. I'm not at my PC to give specifics rn but where you see the resolution settings and stuff that window has another tab and you can override the compression settings to fine-tune it.
BC7 is the best for high quality compression but it also forces you to have an alpha channel. Alpha channel pretty much doubles the VRAM usage so avoid it unless it's needed.
Use DXT1 or 5 depending on whether you need an alpha channel or not but they also usually look worse than BC7.
Sometimes a 2k BC7 texture can look better than a 4k DXT1 texture, so you can save a little VRAM that way too.

>>403612281
What?