Similar story to OP. The MBP I acquired in 2017 has been undergoing rapid disintegration while the 2013 model it replaced is still working just fine.
After stressing over the problem that nothing seemed comparable spec-wise, System 76 released their Adder WS and after reading some testimonials from users online I made the leap back to Linux.
So far, I am very pleased with the choice. Here is what I love about it:
- Amazing 4K OLED display configured with pixel scaling a la Retina out of the box
- Suspend / resume "just works" every time (very different from my past Linux user experiences years ago)
- Connecting an external display "just works" like my MBP
- Pop OS is a well-designed, pretty Ubuntu variant that doesn't get in the way
- I'm really productive on it (I haven't wasted any time trying to get things to work)
- Very high-end hardware all around
Things I don't love about it:
- Battery life is atrocious
- The keyboard has a numpad so home row is offset to the left
- It is rather big (though not gigantic)
- It is rather ugly (though not hideous)
- Huge power brick with a short cable
I can't speak for long-term durability. I guess I will get back to you in a few years.