My intention is to create an ubuntu home server with Owncloud, Roon, and various other apps. Before buying a NUC, I have installed Ubuntu Server on a very Old Macbook White Core Duo with 4Mb of Ram. I just installed Roon Server on it and doing some tests with Flac files and to my surprise, it works without issues.
I am quite surprised…
It will work as long as you are not asking it to do too much. Putting it on faster supported hardware is still prudent but you can run it on what you have until you are ready to migrate.
You can investigate if it is workable for you to run these services through docker containers on ubuntu server. I run roon server, nextcloud, nginx as a reversed proxy and HTTPS endpoint along some other services this way and it works flawlessly.