The only personal electronic communication I use are the only two widely deployed federated protocols: email and SMS. Everything else involves compromises to enter a walled garden that offers no value to me.

Sure but you do understand that makes you the outlier these days, right?

Most people are on Facebook Messenger or Whatsapp or Signal or a dozen similar platforms. I try to use Signal for most communications but have friends and family that won't move to it, so I also use Whatsapp or plain SMS with them.

Is SMS federated though? Genuine question. As far as I know it requires manual each-to-each setup on MNO level thus very fragile when we talk about cross-border or even cross-operator messaging. It is nowhere near email in terms of federation.