I went through a similar set of concerns in summer of 2020. Apple silicon was just over the horizon then. I was unhappy with my 2013 Mac Pro (trashcan). The decision tree was whether to wait for an Apple silicon iMac (or MacPro) or just go with an Intel machine. After considerable back and forth, lots of reading, I decided to go all out with a tricked out Intel iMac which I've now had since August of 2020.
There's still no 27" or larger Apple Silicon iMac and I've been using my Intel machine for over a year and am pretty happy with it. FWIW I use an external NEC monitor for my photographic work. Were I in the same place today, I'd probably do one of two things, either await the Apple silicon 27' iMac (though there's no set time frame), or go with a 16" tricked out MacBook Pro with the M1Max chip, 64GB RAM, and as large an SSD as I can afford. Of course an external monitor would then be necessary as I'd not want to do "critical" work on any laptop screen.
Whether it's cameras or computers, or anything else with sophisticated technology, there's always something new (? better) down the road. Do you want to have something to actually use or would you rather endlessly fuss about what's to come? I don't earn my living with my computer or my photography, so I can go whatever way I'd like. You appear to have made a sound decision based upon YOUR needs, not marketing or endless speculation about what's coming.