I personally like Mailfence. But the others aren't bad alternatives either.
Fastmail is Australia-based, so it's a privacy nightmare. If you're okay with that, it's cheap and works. You get a lot of storage for what you pay.
Tutanota is a German option, but you have to use their email client. They use a custom encryption protocol instead of your typical PGP. They're good, but at the end of the day I like my third party email client.
Mailfence is Belgian and only has infrastructure in Belgium. So they don't even respond to court orders outside that jurisdiction. They offer PGP. Also support IMAPS, etc, so you can use your own email client.
I don't like ProtonMail, and I know this is probably going to be an unpopular opinion, but I don't like them. They have been busted giving client data to law enforcement without a warrant, they don't encrypt the email subject line, they still log IPs like every other service, and they received a ton of venture capital funding. I fully expect their enshittification to happen soon.
Posteo and mailbox(.)org are also options. Never used them so I can't vouch. I hear good things about both though.
And if you're in Europe or have your own domain, Infomaniak offers a suite comparable to Google's at a competitive price. I haven't used it either but it could be good.