I am a Mac user now and have been since I retired in 2010. Before retirement I used Dell laptops (Windows) for many years that were provided by the company I worked for. The company went real 'cheap' on the Dell specs just to save a few bucks even though I was doing some elaborate PowerPoint presentations with a lot of graphics for many years. Those basic Dells were not that good.
Now days I read often that many folks are now quite happy with their PC systems. PCs and Macs are both good these days. Your choice. I would guess that Macs are more expensive than Windows notebooks. But that's only a conjecture on my part.
That said, I am very fond of the M1 MacBook Pro (MBP) laptop that I've had since early 2022. It is both my traveling computer and my 'desktop' system in that it drives my NEC 27 inch monitor. I don't own any other computers (my wife has a 2018 MacMini). My MBP has 32gb of RAM and a 2TB SSD internal (I've read that the M2 MacBook Air can only have a 1TB SSD but I am not sure about that). My MBP was expensive but I am happy with it and glad I spent the extra money to upgrade the basics. And I love traveling with the smaller 14" MBP - lighter and easier to fit in a backpack, etc. The battery life is awesome. I like the larger capacity SSD so I can host the Z9 files on my internal SSD. Convenient, even though I do backup to a Samsung T7 external SSD.
To your situation - a couple of thoughts - if you're using a desktop PC, are you going to be comfortable using a Mac? Are you going to need to create a 'home network' to share files, etc.? It's possible to network a PC and a Mac but it takes a little work to get it to work right. At least that's my limited experience. YMMV. If networking with your PC a windows system might be easier. Not sure.
I am a Z9 user too. Before that I had a Z 7II. So, I've been dealing with 45mp Z9 files ever since I got the M1 MBP. Given the file sizes you might consider whether to boost the basic specs of any laptop to better handle the larger files. A base M2 processor will handle Z9 files OK, but more RAM is better for intensive apps like noise reduction and/or resampling TIFFS, etc. More RAM is better than upgrading the processor specs in my opinion. When you start to edit Z9 files, the M2 (and even the M1s) will impress with their speed. And when you start to edit Z9 files that get sent via plug-ins from one software app to another as a big TIFF file, then the increased speed of the M2 or M1 is a significant time saver.
I cannot draw any comparisons of these Apple Silicon Macs with present day Window notebooks as have not used a Windows product for 13 years. Others can chime in on that. I think something you might want to consider is what machine type will handle the type of files you'll dealing with, what software will you using, and what is the end result of those files (i.e., what are you going to do them final product. Fortunately, over the past year the major software companies that photographers like us use have made their apps work natively with Apple Silicon and now Z9 HE* and HE files will work too. While it's really not possible to totally future-proof your purchase, think about what you need this portable device to do and then find the machine that will do the job. Good luck