I have been trying to create a facebook account recently, for work, I didn't use my real name (I just needed a facebook account to follow some pages). I got flagged and now have to provide additional proof of identity. Same for IG. I don't think it's as easy as before to create a temp. facebook account. After setting it up you need to feed it right.

And when I have to access a 2FA protected account, like my bank or email, I do what?

Even easier: I keep my previous phone when I get a new phone, so it's just a matter of swapping a SIM card. Of course, my old phone was factory reset once I decided to keep the new phone, because I don't want it laying around with all my data even if it is just in my desk drawer.

I'm technically competent and that's a huge, huge deal for me. What you describe is 15-20 hours of work.

I'm far too busy to do that.

This is ridiculous. Put aside the idea of purchasing a new phone for a trip, you then suggest setting up all new accounts and then "telling your friends" - how exactly? contact everyone from your "real" accounts and say add my fake account? What about when you come back - tell them "ok delete my fake account and add my real one"? which is which now, oh and how do you access all your real contacts, credentials, payment, etc that you needed during your trip? And I do this everytime I travel?

You seem to focus on the technical aspects but really gloss over the entire "create a duplicate online life every time you travel"

Honestly, if you need your information to be secure to this of an extent, you should just use a dumbphone and skip all of these lengthy setup steps. And it's cheaper, too!