No sure about 64gb, but for performance/watt and reliable Linux I can really recommend the Amd p16s and t16(s?) machines from Lenovo. Have about seven in the office and they are excellent.

I too, as someone in devops, am wondering what you need that much memory for. Do you simply really like VMs? :)

Also, have you considered doing the really heavy stuff remotely? Whenever I need desktop type power (16 physical cores and 128gb memory) I simply wake the desktop, ssh into it and do it there.

I had an extreme, as nice as it was it kind of sucked on Linux due to all the dual gpu weirdness (working hdmi or battery longevity, pick one)

Has this changed recently? Because it used to be due to the wiring of hdmi though the external gpu

I thought it had to do with the fact that most themes on Linux consist of a large collection of dotfiles, dots, rice. But that might just be me