You say you use Lightroom but make no mention of what camera(s) you are working on. APSC, full frame , medium format etc. There may be some slight difference importing and working on uncompressed RAW files from a 61 MP Sony A7R5, which I use, and RAW files from a APSC 20 MP Olympus. OR do you just work on jpgs? I moved from an Intel 2020 iMac with 64MB RAM to a Mac Studio again with 64MB RAM. The main difference are in import/export, generating smart previews and applying the denoise filter in Lightroom or any other work done in external editors like TOPAZ which is much much quicker. On Lightroom denoise Intel Mac takes up to 30/40 seconds while the Studio takes 10/20 seconds. At the speed one would normally work what with all the tweaking, looking humming and hawing involved any speed increase from the machine is not really noticeable. Exporting a stack of 100 images to Helicon focus, hell yes there is a huge difference. Inside Lightroom not much. I doubt you would see any noticeable difference from the Macs you mentioned. I would say save your cash and buy the least expensive option making sure 16MB RAM is your minimum. Spent any extra cash on good external fast storage. I run multiple applications Lightroom, Photoshop and Helicon Focus simultaneously so 64MB RAM suits me. If you are only running Lightroom then 16 will do though you may wish to consider 32, as who knows what the future holds!
The thing is is we all get caught up in the bigger better hardware illusion. One fact of life that Apple has been no help on explaining is why USB-C data transfer speeds on my Intel iMac are superior to that of my M2 Studio. Thunderbolt 4 is super fast, but no faster than Thunderbolt 3! Hang a USB-C drive off one of these dual ports at the back of the Studioand the data transfer speeds are up to 25% less than on an Intel iMac, or at least on my Intel iMac.
