I was (maybe still am) waiting for the more powerful iMac, too. I mean, make your decisions based on your needs but, for me, the Mac mini is a powerful machine for my day to day work.
I have it connected to a Dell 4K monitor through the HDMI port (mainly because the Dell monitor doesn’t have USB-C). That’s one of the reasons I chose the Mac mini over the portable M1 computers. The 2 USB-A, 2 Thunderbolt/USB-C, and HDMI made comparability super simple.
But, again, buy what makes sense for your workflow. Two or three weeks in and this thing is still amazing. The only issue I’ve run into (and only once) was an Adobe crash, and that was Adobe’s fault.