I have been using X-Plane 12 since the first early access version on my Mac Studio Max | 32 Core GPU | 64 GB RAM.
I use a 49" 3840 x 1080 UW monitor, all settings high, clouds to the max.
At the beginning not many 3rd party plugins were Apple Silicon native, but now most are. I use stuff like Traffic Global, FSWidgets, Better Pushback, HaversineAir, X-ATC chatter.... all work great natively!
First couple of betas had some performance issues with the new volumetric clouds and sunset-colours, but these are ironed out for some time now.
I make use of many scenery add-one like orthophotos, SIMHeaven X-Europe, pay-ware airports and other sceneries (lots of Orbx TrueEarth stuff for instance) and the performance is stunning!
Settings as described above and easily over 30 FPS, that is flying low over London approaching Heathrow, or over Manhattan, or L.A, only sometimes dropping towards 20 - 25 when approaching Amsterdam airport (for whatever reason....?). All other "heavy scenery" work great.
I must note that this Mac uses c.a. 40 GB of RAM total when flying low over heavily populated areas.
GPU between 75% and 99%
CPU between 140% and 175%
Only during loading does X-Plane use all cores.