[Eisenstein]

You just reminded me about wildcard email forwarding. If squarespace turns that off I am screwed. Do you know any providers which will keep it?

[josephb]

https://purelymail.com/ https://mxroute.com/

Are two providers that I've used to catch-all and forward to an external mailbox.

[kstrauser]

Namecheap has it for free on domains registered there.

[peddling-brink]

Cloudflare supports it.