So after almost a month, I can finally say something constructive on MBP16 vs X1E.
First of let me start by saying that this will be very subjective opinion. I'm not reviewing devices, and I honestly can't do that. What I can do is just say how they compare to me and for my usage.
MBP 16 is really a great laptop. Screen on MBP 16 is way better then screen on X1E. Mostly because it's 16:10 aspect ration, and it's larger. But also brightness is higher, it's easy to notice even in my office. Also, battery life on MBP16 is WAY better then on X1E. I can easily go beyond 8h of working on MBP16 without external screen. But only if I'm developing mobile apps. If I turn on Unity or Godot (game engines), well, I can get around 6h or so.
On X1E I'm lucky if I get 4h under Ubuntu while doing mobile apps (flutter, likewise on MBP). Under windows 10 I can get around 5h30min max. While doing game dev stuff, it becomes way worse. In this category MBP16 wins easily.
As far as noise goes, both are good. I see that a lot of people complain about noise on MBP16 while connected to external display. But even though temps do raise, and fan rpm does raise, I can only hear fans while in really silent room, and if I put my ear next to MBP. So my unit probably got lucky with fans.
X1E is likewise almost dead silent most of the time. Both will ramp up fans while being pushed. And that's to be expected. But neither has some irritating fan noise.
All is great so far... But where X1E easily wins is keyboard. MBP16 returned to the old magic keyboard, but key travel is still too shallow for my taste. And what completely destroys MBP16 is the touch bar. I can't really express my frustration with that gimmicky thing. It completely ruins my workflow. In order to be productive with MBP16, I really have to use external keyboard.
Another thing is lack of ports. I get 2x TB3 ports with X1E. More then enough for me. But I also get almost all other ports one can need or want. In MBP it's just usb-c. And that is something one can deal with, but I refuse to do so.
I love Linux. I love every aspect of it, except one. You won't find a lot of apps MacOS or Windows have. Like Adobe, MS Office, Affinity, etc. And some of those apps I use every day, and I need them. But with X1E I can simply boot to windows10 when needed, and use linux rest of the time. It's a compromise I'm willing to take.
MBP16 is really great. But touch bar is simply compromise I'm not willing to take. I'm the kind of guy that really needs function keys. I'm a developer, and most developers use functions keys a lot. And I do mean a lot.
Seeing that Apple is stuck with touch bar, and they have no intentions on dropping that gimmick, or at least offer a choice, I'm afraid my time with Apple is probably completely done. At least for now.
And during the time away from apple, I've found love for Linux. I love customization options, I love that I can change DE just for fun, I love command line and all available tools for command line... I love it.