There are a lot of laptops like that in the PC market, more skewed towards gamers. I like Dave 2D's youtube reviews (no affiliation) of laptops: https://www.youtube.com/watch?v=NLsDn59fxdQ
He has a whole bunch more on his channel about others similar to that lenovo.
I've looked in to most major brands (Dell, Lenovo, HP, Razor) and can't find any offering with 64GB RAM + discret 4GB CUDA card + 4K resolution + 2 SSD + 1 spinning drive + Linux support.
If you know any other options, I would be happy to know.
He has a whole bunch more on his channel about others similar to that lenovo.