Maybe some custom TXT record to let mastodon find my thingy.

Anyone know if I can CNAME (or something) one of my personal domains at a host so my username stays stable but I can switch providers transparently?

mastodon.cloud

[Notice Regarding the Transfer of the mstdn.jp / mastodon.cloud Services] We have received several inquiries showing interest in a transfer following the announcement of the end of the mstdn.jp and mastodon.cloud services. As a result of subsequently evaluating the situation and making preparations, we have decided that the corresponding services will be transferred to Sujitech, LLC. on June 30. Thank you.