It will have no problem running a 4k monitor at 60 hz. However, using a usb c to display port cable instead will give access to a scaled resolution to 3008x1692 that looks very nice, but I normally run in 3840x2160 the vast majority of the time.
bbednarz, it sounds like your monitor that is being fussy has HDR turned on. In the displays panel of System Settings/System Preferences uncheck the box associate with HDR and things should look better. For whatever reason Apple's implementation of HDR for monitors doesn't seem to do what you expect as a user and things appear washed out. If that doesn't fix it, check rtings.com to see if they tested that model and what their monitor settings were. It may help dial it in a bit better.