Hi there blueboybythesea. I’ve got a Dell 27” monitor too( 2713HM) , and it’s working fine. Does 2k, not 4k. Got empty-wallet-itis. Ocassionally i do have to unplug it, but not too often. Like you i was surprised that dell doesn’t play nicely with Mac stuff.talk to Dell and they’ll tell you to talk to Apple, and vice versa. Nevertheless, it works-basically. What worked for me was an EDID override for dell monitors on Mac. Just follow the instructions when you find it. There are 4k monitors out there with Mac compatibility so if you are really unhappy with the Dell, and you are within the time allowed for returns, and the vendor accepts returns, you may wish to do so-however if not-then you’ll just have to make the best of it. I’d suggest using mini displayport and turning on MST on the monitor( i think this is for 4k)
Just my 2 cents
John B