Oh yeah I was thinking of sim swapping. Thanks.

TOTP gets a little tricky when it comes to phishing, but only because most phishing attacks that target casual users (rather than spear phishing attacks) aren't capable of logging in immediately. Naturally, that would change if enough people started using TOTP, but for now, TOTP is enough to avoid becoming low-hanging fruit.

Of course, if you're a high-value target or work for a company that's likely to be targeted by spear-phishing campaigns, you should be using FIDO2. (Don't target U2F, as there are newer, backward-compatible specifications.)