Yup. I got yunohost.org running on a free instance on Oracle cloud (using a PaYG account) but costing nothing. - Ive then spun up an Email, Frendica server (limited to users on my domain) and Takahe to try out ActivityPub.
I think that a killer app for activityPub would be if MSFT or Google offered it as a service on Workplace / Office365 . (I mean Id rather not use either of them myself)
Wow this is cool. Do you use OpenWrt at all? It would be amazing to integrate with its DYNDns package.