32" LG 32UP83A-W 3840x2160 4K UHD IPS FreeSync Monitor w/ 60W USB-C Expired

Bought "Acceptable" condition from Amazon for $299. Received almost brand new monitor.

Are you speaking from experience? (edit: I see you said "in my experience"; I guess YMMV) To me, macOS scaling looks great on 4k, regardless of whether you are doing 2:1 scaling (e.g. 1080p equivalent on a 4k) or something like 2560x1440 equivalent. I've used it both on 32" and 28" 4k displays. I currently use a 27" 1440p and it is a downgrade from 4k. Only reason I'm using 1440p is because I work from home and I also use it for gaming, though I eventually want to get a 4k high refresh rate monitor.

I also have an 5k iMac. It looks sharp (in any scaling mode) but a lot of that is the glossy coating vs how matte coating can make displays blurrier. I've also noticed this difference with glossy 1440p displays too (glossy 1440p Apple Thunderbolt display vs my matte 1440p gaming monitor). Glossy can have the disadvantage that reflections are annoying, but I hear Apple's current 5k monitor doesn't have this problem.

In general I find macOS scaling is really good and allows me to switch between various equivalent resolution modes depending on what I'm doing, how I'm sitting, etc. I've been using scaling since 2012 when the first Retina MacBook Pro came out, and I'm often not using 2:1 scaling and it looks great to my eyes.

That said, if you are on Apple Silicon I would research any 3rd party monitor to make sure it works well, as some people have issues with specific monitors.

This is a bit of a misunderstanding. Macs do 4K great…if you like 1080p scale on a 32 inch Display. Macs do 2x scaling for retina. So a 4k display in best scaling mode will appear 1080p. 5k is 1440p. So a 24 inch 4k or 27 inch 5k are best generally.