Yep there being metadata, and it being abused, are also two subtle differences. We know with WhatsApp there is metadata including IP address, location, phone number, etc, but it also gets actively sent to a company (FB) whose business is to profit from that data and advertising. We know Telegram and Signal have some metadata but neither are in the business of selling data. Yes Wire, Threema, etc don't have as much metadata and don't have an actual phone number or e-mail to even tie it too, but how many of our friends are actually using the services... There has to be some dose of actual reality too.

Hosting own e-mail has some issues unless you put it on some server service and the domain is usually tied in some way to you, and yes that e-mail is often accessible in transit because again 99.99% of our friends and businesses that we mail, have not got OpenPGP or similar E2EE on all their e-mails. I have only one family member who exchanges fully E2EE mail with me. Every other one is using GMail standard or a work server etc. The fact of life is that very few people are able to fully setup e-mail servers with all the validations etc required so that the server is not blacklisted. I can just imagine my doctor, plumber, local hardware shop, etc all setting up their own privately hosted and fully encrypted mail servers - I just hope they're using the same encryption standard I'm using otherwise neither of us will read each other's mails ;-)