I am not a professional photographer, nor do I play one on YouTube but here's 2 cents that will just fill up your pocketbook.
At this time it appears that going forward the manufacturers will be phasing out production of the SLR/DSLR lens mounts in favor of the mirrorless mount. Canon announced some time ago that they will no longer be developing or releasing any new EF (SLR/DSLR) lenses and focusing on the RF (mirrorless) series. Nikon also has a new Z mount and adapter for older F glass, I'm not a Nikon shooter so I don't know if they are abandoning the F glass like Canon.
Both Canon and Nikon have adapters that allow SLR/DSLR glass to be used on a mirrorless body but the new lenses are not reverse compatible due to the sensor in a mirrorless being much closer to the mounting plate. Buying a mirrorless now will allow you to take advantage of both types of lenses. Sony has been using mirrorless system for some years now and there is a good selection of used equipment on the market that uses only one mount.
Moving on from facts into the realm of opinions.
Brand loyalty is what it is, not going there. If you are buying a body and you have a bag of lenses by all means stick with what you have. If you're starting fresh, find a body that feels comfortable in your hands and ergonomically works for you both physically AND in the menu system. Don't laugh it can be a big issues if your brain doesn't work the way your camera does. Nikon, Canon and Sony all have a excellent selection of bodies and lenses and the image sensors are very similar in performance for the majority of us.
What is just as important, if not more, is to learn to use an editing package like Photoshop to develop your pictures after you take them. In today's technology just like the days of chemical darkrooms the business after the shutter clicks is what makes the photo outstanding.
Edited 1 time(s). Last edit at 05/26/2020 11:13AM by Paul Dalleska.