

You can get motherboards with enough slots if you’re willing to pay enterprise prices for them. I have a system with 1TB of RAM at work that I use as a fast data cache. I just mount tmpfs on it, write hundreds of gigs of data into it (overwriting it all every few hours), and it works great. Cost was somewhere in the $10~15K (US) range a few years ago, IIRC. Steep for an individual, sure, but not crazy for an organization.
Pretty sure you can do much better than that now (plus or minus tariff insanity) – quick check on Amazon, NewEgg, etc. suggests ballpark of $5K for 1TB RAM (Registered DDR4) + probably compatible motherboard + CPU.