Thinkpad L14 Gen 3 AMD works with 64GB RAM and has a fast CPU, though there are of course faster ones.
Chassis is mostly plastic though afaik. The T series from Thinkpad use higher quality materials, however there were no models with 64GB RAM last time I looked, and it is partially soldered. They did have a model with max 48GB RAM, but that was 32+16GB so it is slower because it isn’t dual channel.
If you’re interested, here’s my HCL:
https://forum.qubes-os.org/t/amd-thinkpad-l14-gen-3-ryzen-7-pro-5875u/