There are a lot of good posts about de-googling your email, but they all seemed to be focussed on single user accounts.

Does anyone have a good guide for de-googling my *family* email?

We need to migrate existing inboxes/archives, sort out hosting, re-point DNS (MX records, etc.), and we need Android and iOS apps.

And it needs to be relatively trauma-free.

UK/EU solutions only, plz.

#degoogle

@rogerlipscombe I use an el cheapo Hetzner webhosting server which comes with unlimited mailboxes (though I'm only using one). The webmail is a bit clunky compared to gmail, but I almost never use it 'cos it also supports proper IMAP. I can recommend it as a destination, but I appreciate that's not the same as a guide to getting there starting from a well-stocked multi-user gsuite.
@TalesFromTheArmchair @rogerlipscombe I'm still running my own mail server with IMAP. Outbound delivery goes via my ISP. I even use offlineimap to insert mail into GMail mailboxes for those that currently use it as their mail client. How much longer this is sustainable for I can't say though, and Peter's suggestion seems like a better idea. https://disconnect.blog/getting-off-us-tech-a-guide/ has a list of commercial email providers too.
Getting off US tech: a guide

I’m in the process of dropping US tech services. Here’s how I did it, and options you should consider.

Disconnect