Forgot to provide the specs for my 15 2018 MBP, which was plenty powerful at the time I purchased it and still is: i9 / 1 TB SSD / 32 GB RAM / 20 Vega. I use it for editing image files from my Sony A7R IV and other cameras as well as of course everyday stuff such as emails, web-surfing, participating in forums, etc. The 24" monitor is great for doing my photo editing work. I know some people prefer larger monitors, but I have tried them in the past and for me 24" hits the "sweet spot," so to speak.
I store most of the image files away from the internal 1 TB SSD drive, using mainly Samsung T5 external SSDs and also a couple of Samsung X5 NVME external SSDs, keeping my computer's internal drive "clean and mean" as the saying goes. I also have archival HDD drives as well. For a photographer, having good backup drives as well as those which are considered more supplemental and meant to retain current files for a while is very important.
Back in 2006 I tried the Mac Pro route when the first generation came out, and while I really liked the machine, it was terrific, I eventually had to admit that it really was overkill for my uses and needs, and after a while I sold it to a friend. I loved some things about it -- a major one being able to have four drives within the machine -- but there were other aspects, along with the sheer physical size of the thing, which just did not work out well for me and I realized that I really did not need such a beast of a machine.
I've also tried a Mac Mini (I think that was 2009/2010) and while I liked it a lot, too, eventually decided that really, I am most happy with the flexibility and portability of a MacBook Pro. I've had a few now over the years, and for me, each has proven to be very portable, flexible and responsive to my needs, and a machine which can be expanded in capacity by simply plugging in an external drive or two takes care of any storage needs.... I am not hampered now by a desktop machine at all. I can decide to grab my 12" MacBook and throw it into a bag to go off on a short weekend trip [whenever that will happen again in this day and age!] or I can decide, if the trip is one more focused on photography, where I'd be doing a lot of shooting, to take along the 15" MBP, and again that would simply be a matter of unplugging the monitor and away we go..... For me, flexibility and portability is the name of the game.
Everyone has their own criteria for what works best for them and what they really need in order to be sure that everything works best for them. Sometimes it takes a period of trying out different strategies, different devices, etc., before finally arriving at "the" solution which actually works. I spent quite some time in analyzing to death whether or not the concept of a MacBook Pro mounted on a stand used as a "desktop replacement" with peripherals connected would be the right solution for me, and back in 2015 I decided that, yes, it was -- for me. Someone else might arrive at entirely different conclusions for different reasons.