FYI, Amazon (retail) does support TOTP. Here is a direct link to the 2FA settings so you don't have to crawl through the account settings page looking for it: https://www.amazon.com/a/settings/approval.
Paypal supports TOTP everywhere, but it’s hidden on a page not reachable via any of their sites, in their old site, and you need to run a custom python script to even generate the token you want.
Wow, that is horrible. Given that, I would argue that, for all intents and purposes, they do not support TOTP then. An average user has zero chance of doing all of that correctly. Bummer the don't support it as a first class citizen in their security UX on their main site.
Care to share a direct link to the TOTP configuration site though?
PayPal and Amazon both support TOTP, including for all support contacts, but it’s hidden. Personally, I’ve enabled these.