The problem at this time is the challenge of getting either solution to host but at this time there may be services that do that for you. Hosting yourself could give you peace of mind that vital files are strictly in your custody.
I have been working on a wizard installer for both with nextcloud but the release is still far off due to my quality concerns.
With wildcard aliasing offered by most email providers you can have that email address be anything you like, like googlesucks@your.domain.
It might kind of go against the whole de-googling depending on your outlook though.
Source? I haven't heard much about this space in a long time now, and due to that I get the feeling that it's kinda meandering.
It isn't even very good, or have many features, but still seems to be the best.
In my opinion, the area is ripe for disruption, but I suspect nobody wants to spend their life re-reinventing the word processor in javascript.
If I did I guess I’d create a minimal google account with as little info as possible, ensure it’s security / privacy settings were set as restrictive as possible and then have to settle for using a Firefox container just for google sites (there’s a good pre-made on on the extensions site), you could go as far as also spoofing your user agent etc but that might just be more of a pain than it’s value.