@Legaltech mastodon may not run well on one SBC besides playing around in a single user setup and definitely won't do it with elasticsearch enabled. You need to commit 4GiB+ of RAM for a Mastodon instance to run smoothly.
However mastodon is not a monolithic architecture so it's components can be distributed amongst multiple ARM SBCs. I think @asonix still runs asonix.dog on such a setup.