Good luck with whatever you decide and please come back to let us know.
Here is one more thing I will mention. I am sure you know it, but it easy to not think about. It has to do with multi-tasking with multiple high memory usage programs running at the same time.
The 32gb memory would likely work very well even working on 200mp photos, but you would probably find it would do much better if when you are working on one you get out of any other programs that that use a lot of memory (such as a browser with a bunch of open tabs).
For people who do not mind spending a very large amount of money for the maximum memory, SSD size, etc. then, of course, this is not an issue for them, but for most of us we are trying to decide what to get while balancing cost, what will be adequate, and what we desire -- which often is much more than what would be adequate.
Running only the main program (Lightroom Classic or whatever) when working on a huge 200mp file would probably mean you could get excellent performance without going to 64gb or 128gb memory. Sometimes we have to make compromises. Probably you are not working on 200mp photos throughout the day, every day so most of the time having multiple programs running would not be a problem with 32gb (or 16gb for that matter), I think.