I've experienced some serious bugs on ProtonMail, one of them being that a saved draft from the desktop web app subsequently sent from the iOS app doesn't show

I've experienced some serious bugs on ProtonMail, one of them being that a saved draft from the desktop web app subsequently sent from the iOS app doesn't show up in the sent mails. I've since switched to Tutanota which I'm very happy with and is in some ways more secure. It doesn't support third-party clients for security reasons but theirs is open source. And to top it off, it's significantly cheaper...