The scale-down floor for running an ATProto relay or appview is much, much higher than the floor for running a fediverse instance.

You can scale down as much as you want. You don't need to run full relay if you want to follow only a dozen of accounts. I bet you can run something like that on a raspberry pi or something similar. You will not get the search over all of the network, but that's something you don't get with your personal mastodon instances either.

Since sync 1.1 last year, you can run a relay on a relatively small VPS