It is cheap as long as you don’t need to restore your data. Downloading data from S3 costs a lot. OP asked about 56TB of storage, for which data retrieval would cost about 4.7k

https://aws.amazon.com/s3/pricing/ under data transfer

If it can be installed on arch, it can be installed on steam OS. You just have to jailbreak it beforehand, as I said in the previous comment.

Can’t be worse than trying to fix dependencies for maven on any platform

I installed some games from GOG on the steam deck. The hardest part was trying to figure out how to make them show up in steam library. For software that requires modifying the system, you’ll have to jailbreak the steam os. It’s quite straight forward and irc it took me about 30min to enable sudo and install ydotool for autoclicker.

New drives are more like 20€ per TB. Factor in redundancy with something like raid 5 and boom, off-site storage costs you a government toppling 20 000€ in hard drives.

It is doable, but it is a pain if the docker requires any special config like permanent storage. Getting nginx up and running for mTLS was especially annoying

Truenas Scale works well as long as you don’t want any dockers on it. Once you want to run docker images it is easier to install a VM on Truenas and run the docker from there than it is to try to set up custom “Apps”