Interesting. I have always used their web app (even on mobile, i just use their pwa instead of the native app since the native app is missing obvious features), and I haven’t had any issues, but I can definitely understand the frustration
Don’t get me wrong, I’ve nothing against you… but…
This is the irony with the privacy minded people and anti-google / monopoly folks around here - they can’t use Google and Microsoft because of the monopoly and then use a solution that is 10x more closed and doesn’t even has an option to use standard protocols and email clients. Logic ham ? :P