Just commenting based on the title since I am blocked from YT and also don’t speak German. (An English transcript would be useful)
Ditching Gmail is trivially easy. Boycotting gmail is where the interesting conversation is, because often you need to reach someone who uses gmail. You can do an MX lookup on the domain of the recipient’s email address, but that only works about 70% of the time. If they use an email firewall like Barracuda or a forwarding address, then there is no way to know where the email route ends.
If I cannot get confidence from an MX lookup, then the recipient is getting a fax or postal letter from me. Google could still end up in the loop, but as long as you don’t reveal an email address to the recipient, at least you remain in control over what Google collects and profits from.
Thanks. I noticed that but I would have to wait till I have a decent connection and then I wouldn’t understand the German anyway.