The Studio Display is only marginally better than the display in the 5k iMac. I have a 2020 27" iMac and plan to hold on to it for a few years at least. The fans only ramp up when I am using all 10 cores, otherwise its nice and quiet.In terms of the performance, the 5K panel in the Studio Display is best in class for an LCD - proven to be better than that of the 27" iMac - and in suitable lighting conditions (that being, not a pitch black room with the display brightness set to max, like YouTube reviewers "real world tests") the lack of mini-LED would not compromise a content creator's workflow.
So the question remains; do you wait until Apple can get a decent margin on 27" 5K mini-LED panels, or buy a new product that will satisfy all but the most demanding creators?
I bought the iMac just after the Apple Silicon announcement but before any retail hardware was announced. I did so because I planned to wait out the first few years of the transition. This was not because I doubted the hardware but the software ecosystem needs time to catch up.
We are almost two years into the transition and critical software I need to run is not yet available in native arm versions. Other software I want to run is not available at all for Apple Silicon Macs (VMWare, x86 Windows, x86 Linux, x86 Docker images).