Sharpness is often defined by image post processing in firmware or other shenanigans of driving the panel itself. Reviews almost always do not bother to check this so you're left with user reports, of course best is to get a monitor and check it yourself and there are also test patterns to help and show the sharpness issues easily.
Clean? That would mean to me a glossy surfaced panel. These are quite rare these days.
Resolution, panel type, size, has no impact on either of these.
Of course high density panels are better at showing fine detail but can suffer from scaling issues in modern OSes.
Would not touch a low density 32" 1080p with a ten foot pole because I would have to be more far for text on it to not look gigantic.
27" 4k... you will probably want to use 150% scaling in OS as 200% can be a bit too much, but it's a decent size and density.
99% of my "sharpness" comes from the OSD on my ASUS ProArt 10Bit 4K. I have 2 different sharpness effects I can apply. Why this would do you ANY GOOD on a "pro art" monitor?!?!?! idk.
well, ok... 75%, 25% is game/software decided.
R.I.P. Zawarudo, may you OC angels' wings in heaven.
VA often has large black space, can have split pixel layout and split pixel dimming, all of these can make those VAs look subpar to traditional low black space, full pixel layout, full pixel dimming IPS and TN. These all can make the panel look less clear and harder to read from.
TV VA (40"+) tend to be BRG not RGB which can matter to you if you use subpixel smoothing or the application you use does, but I think ClearType if you use that abomination can be returned for BRG and Linux (Solus at least) supports RGB, BRG and their vertical variants for font smoothing.