I use an LG 27" 4k on my Mac mini and used it on MacBook when I had one, resolution is fantastic and build quality is good too. I had a Samsung 32" Space monitor which devloped a noise, so sent it back under warranty, they broke the screen and wouldn’t replace it - even had a video showing it working fine when it arrived. As a result I won’t go near Samsung stuff again…
The big benefit of the LG is the USB c connection, for a MacBook it charges it whilst displaying so its single cable. Since I sold the MacBook I still just use the USB c for Mac mini and it enables the drive ports on the back for USB if I ever want to use them.
@bowline is spot on though, the resolution naming is just a marketing thing from my experience, what matters is the PPI which will normally decrease over 27" just through the physical size which is natural.
I have the 27UK850 and paid around £400 in March for it. You can get the same model but cheaper without the USB c.
My only thing I would change is possibly having a widescreen, I have to use a PC for work and Picture by Picture on a 34 would be beneficial. Another deal breaker for me was having speakers built in, they are not great but do fine for listening to music whilst working etc.
edit: meant to add the finish on monitor screens are predominantly matte which will add to it looking slightly different to the MacBook as it has a glossy covering - I am sure there is a technical name for that.