Having been a dedicated M-user for 50+ years, I did add Nikon Rf to my arsenal about a decade ago. Mainly because I was curious about the system and wanted something different - as well as a system that did not involve "work" for me. Anytime I use a M camera - that usually means testing a winder, grip, softie etc.
The Nikon is different - but similar too.
Great viewfinders, particularly the S2 and to some extent the S3. "Back door" loading - though you have to figure out what to do with the back when reloading!
Some of the classic great Rf lenses. The 50f1.4 even in its earliest version rivals Leica's any day. They are also smaller, more compact lenses in the 25/28/35/50 range - and gets rather "muscular" in the 85/105 range!
It turns backwards from the M - but it has a very long throw - 270 degrees. A bit slower than the M, but also a more precise focus point. I suspect that the reputation for some of the Nikkors has more to do with this pin-point focus than anything else.
The fact that there are less lenses is better for GAS attacks. They are either reasonably priced (28/35/50/85/105/135) or so expensive that you wont even consider them (21/4, 25/4/50f1.1/85f1.5/105f4).
Initially, I would get one body with the 50f1.4 (S3 Millennium and the matching lens) and see how it works out. Dont switch the system in it's entirety at the start.
If you do a lot of people shots with medium long lenses - also get a 105f2.5 - no better portrait lens made and great as an allround landscape lens too (S3 has the finder for it built in).
Dont try to mix while shooting. I have found that using the M's and the Nikon Rf's at the same time results in a lot of "refocussing" as you keep forgetting which direction it turns.
It is stlll a reasonably priced system. For what a MP costs new, you can get a good Nikkor kit. A couple of S3's or even a S3/SP, 35f2.5, 50f1.4, 85f2 and the 105f2.5.
Another factor to consider: Over the years I have found that my Nikon's stays in shape better than my M's. Less problem with viewfinder/rangefinder alignment, less problem with shutters and I have never had an advance/rewind give up them.
Parts, if you need repairs, are scarce though and few tech's around for service.
Also, be warned: Nikon Rf's are highly addictive! I started with a S and a S2 and a couple of lenses. Now my stash of bodies rivals my M2 "herd" and as for lenses - almost as many as the M-system - including a couple of "collectible's" (25f4/105f4).