If you have enough power on hand you can render games at up to 8K [0], and downsample to your monitor's resolution if you're exceeding it. The textures are the original 1080p assets, but it's still a huge boost in visual fidelity, especially if you're downsampling (there are also usually mods to disable a game's native antialiasing if you're doing this). If a game wasn't even attempting 60fps on the Switch in the first place, there are usually mods to unlock the framerate.

[0] https://blog.ryujinx.org/introducing-resolution-scaling/