16GB is enough for the sort of work that I do. But if that's not sufficient for you, you could get the X1 Extreme which is the "Pro" version of the X1 Carbon, or you could get the Thinkpad P1 (ultra-portable workstation) or even a Thinkpad T series (corporate focused - cheaper than X1 & P series). X1 & P1 have a Carbon fibre chassis which is why they are more expensive than the T series, which has a magnesium alloy chassis.

The newer Thinkpads are not as extensible/repairable as back in the day. However, anything is a significant improvement when compared to the horrible dictatorial ecosystem of Apple.