Earlier quoted context omitted.
I did the same and am a big fan of their services. Still, a word of caution: their policy states that they delete emails in folders named „Trash“ and similar after 30 days. It is documented, but I realized it too late. And the list of folder names in the docs is „non-exhaustive“. https://www.infomaniak.com/en/support/faq/2351/understanding...
I thought this was a standard procedure? Especially for someone who is used to GMail. In fact, I was surprised when I found out that Proton doesn't do that, and also doesn't empty the Spam folder.
Now that I looked closer, you seem to be right. Hotmail does it as well. But Gandi didn't back when I used it, and MxRoute doesn't. That's probably why I was surprised.