Lightroom has always worked on both Mac and Windows.

Photos, the built in photo app on Macs lets you do minor edits but isn't sufficient for stock photography.

Go to Apple's site and look at your options - without knowing your budget, your goals, the size of your portfolio,
what cameras you are shooting with (the size of files you'll be working with), it's impossible to make a recommendation.

You can spend upwards of $7,000 on the new Mac Ultra and peripherals, depending on so many variables, or even more on a Mac Pro (base price $5,999 - then you need a monitor, keyboard, mouse or trackpad) or you can get a Macbook Air starting at $999 or an iMac at $1299. So many iterations in between.

First step is to check available options:
 https://www.apple.com/mac/compare/
Next, contact Apple and get recommendations.
Then come back here and ask more specific questions once you have a general idea of your needs.

I'm considering replacing an old iMac and have been looking at the new Mac Studio which I'd pair with a BenQ monitor (the monitor doesn't have to be from Apple). Another option is just getting a monitor and using it with my 3-year-old MacbookPro (which cost $4,000 a few years ago - I "future proofed" it with 32GB RAM, a 2TB hard drive, and fast processors to make it my primary computer since my iMac was already old. The only reason I'm considering the Mac studio is that I've already had to replace the battery and keyboard on my MacBook, so I'm leaning toward a desktop as my main computer again. My battery went just before the extended warranty ran out - I've had other issues with laptops and find it's worth the price to get that warranty - at least for laptops - desktops seem to last longer).

I don't know about video but I find that given the way I work, usually with Photoshop & LR Classic both open along with several browser windows, and working on 42 & 61MP images - sometimes many layered PS files, the power of a fast processor and 32GB RAM has worked well for me, so has having a large hard drive with enough empty space to keep things running smoothly. Though with the new M1 chip, I understand the machines are more powerful without the need for as much RAM. Personally, I still wouldn't go with less than 32GB RAM but Apple can advise you better than I can.

Future-proofing makes sense in my experience. For example, my 2015 MacBook Pro with 8GB RAM wasn't cutting it when I went from 12-16MP Nikons to full frame Sony's which coincided with major upgrades to PS & LR. So I had to upgrade even though the old MacBook was still working well. Think about your current needs & where you'll see yourself in 3-5 years and get the best you can afford.

With fast external SSD drives, you can save on hard drive size, but be sure you get enough RAM and a machine that's powerful enough for your needs within your budget.

Good luck. A new computer is always fun!