Maybe some type of long physical probe you have to sit on and it generates a hash from the exact shape of your "cavity".
Seriously, am I the only one who was happier without any of this "2FA" crap? VPS/Domain/Google with a hardware token is the one narrow scope where I see any value, and even those I could do without. Every other site is just a non-consensual nagging that hassles me when logging in. Bank accounts are the worst, as every bit of friction for checking my balance/transactions actually decreases my security!
Unfortunately security theatre is viral, and nobody gets paid saying we should have less of it.
As op, yeah I'm actually with you on this.
And at the very least, 2FA should be a much more "openly open standard." Which is to say, just do TOTP everywhere, let people have their initial generating key and be done with it.
I generate mine from my computer when I can, but I'm surrounded by all this magic that implies that something different is going on, e.g. the Duo system which I'm forced to use by my job and doesn't make this sort of thing easy, if possible at all.