I get “This device does not support passkeys” on Sony Xperia 1 V running android 14

If they don’t have support, how do they know what’s a frequent question?

Https does not make the chats encrypted

I found it a bit dodgy when companies use outlook or Gmail instead of their own domains for emailing

No one said that Thunderbird keeps copies of your email. But there are apps that do that and the OP does not want one of them.

No, I am saying that OP is looking for an alternative client, which also doesn’t upload their emails. For example, mailspring would be a bad recommendation because, as far as I know, it uploads your email to their server

They mean mail apps that keep a copy of your emails in their servers

Tokyo drifts?