Ask HN: G Suite alternative due to legacy ending?

Gmail is ending its G Suite legacy soon, and I've set up my entire family on there with a custom domain. The cheapest option $6 (USD, presumably) / month / account is not affordable as by now we are already 8 users on our domain (and more might be coming!).

What's your experience with other email providers? I'm looking into something less expensive so I'm undecided between Fastmail and Tutanota (already have the free version).

What are your thoughts? Any experience with these providers with your own domain?