I use Nikola and it hasn’t let me down. It just works and supports all the ways I write content: markdown, asciidoc, rest, Jupiter Notebooks, html and so on. It does not have so many themes, but the default one works and it’s not hard to customise if needed. If you like to use python it’s also easy to extend. I’ve written a bit about Nikola here in case it picks your interest.
I’ve deployed it to CloudFlare pages, but GitHub pages, Gitlab pages and any other provider also work.
I use infomaniak email with a custom domain. Is around 2 USD per user with unlimited storage. The web UI has an email import tool that works with Gmail. You get a manager UI to manage accounts and settings (sometimes a bit confusing, but works).
After checking many providers, this was the best alternative for me. I hope that helps.