Hi,
- Should I use 1 email for all or 1 coin?. Eg: 1@1.1 for Bitcoin, 2@2.2 for Ethereum, ... or allinone@email for Bitcoin, Ethereum, ....
- Should I use Gmail or secure email like ProtonMail, Tutanota for coins?
What exactly do you mean? Bitcoin nor Ethereum is stored in a mail account. They're stored on adresses. I'm not exactly sure what you're referring to here?
You want to use a different email for each exchange, or something along those lines? Would be better for your privacy, not so much for your security. ( But most exchanges have a KYC policy so i guess it doesn't really matter.)