Questions about the resolution settings

[Goshorai]

Say, is there any reason as to why there's only up to 10x the resolution of the PSP?

I mean as of now, that should be enough even if you want to downsample since 10xPSP is actually higher than 4k. But why is the cap there? And why there aren't arbitrary resolutions? Is it a limitation of the way the PSP is emulated that only allows for multiples or a deliberate choice from the programmers?.

Does the "Auto" option support more than 10x PSP? Say, 8K (7680x4320)?

[TkSilver]

You start to get diminishing returns as you continue to go up in resolution, especially since the source was not really designed for it.