Maybe something like this?
Personally I prefer workstations. They might not have as high of a compute density as a rack server, but you can properly cool them so they run silent and there is less proprietary components. I got a good deal on two of these D20 Workstations Refurb.
Then I installed this 120mm CPU cooler on each CPU, replaced the case 120mm fans with some silent ones.
https://www.amazon.com/Cooler-Master-RR-212E-20PK-R2-Contact-Renewed/dp/B07JZTZ2RZ/ref=asc_df_B07JZTZ2RZ/?tag=hyprod-20&linkCode=df0&hvadid=312780390407&hvpos=1o1&hvnetw=g&hvrand=9341135070449957251&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9053049&hvtargid=pla-663102950637&psc=1
And these machines are basically silent under full load, they also have room for dual GPUs and 6 HDDs. They generate around 6-7k Boid Power each from the CPUs. Only downside is they are older Xeon CPUs and pull a lot more power than more modern hardware.
