The whole S3 sleep fiasco is the stuff of nightmares. I have a gen 6 X1 Carbon too and I've gotten it sleeping very well. I also have a Dell XPS 15 that I love but... it's been 2 years since it was brand new and it's still stuck on S2 "idle". As I understand it, Microsoft wants it this way so they can maintain network connectivity. My major gripe with the Lenovo is the 16 gigs of RAM soldered on the board. It's so nice to be able to pop open my Dell and put up to 64 gigs in there, while replacing the SSD in one of the two M2 slots.
Then again, I'm typing this on a 2019 Macbook Pro (Intel) that has nary a single replaceable part.