Thanks for sharing.
Yeah, when I first looked at the design of ActivityPub I worried that it sounded resource intensive to scale, and then when the Twitter exodus happened I heard a ton of people on here complaining about that exact concern.
So it's something I keep an eye on, though I haven't run it myself to have first-hand experience.
@volkris @jeff yes I also host a little mastodon instance. The requirements in mass storage was a surprise for me. I would say 10 times bigger than for the pod. But the pod was for a few friends (8-10 active users) and the instance is a little bigger (29 active accounts). And our personal data usages have grown.