When I realised the issue was specifically with eBay's .co.uk sign in URL I did as you did and logged in via .com. When I first tried to go to a "sensitive" area (account settings) I received the 2FA prompt for a text code but the code was never received. I then switched to using a passkey but ended up in a loop where the correct passkey just returned me to the original prompt for a passkey. I then noticed I had the option to use a password and that worked seemingly bypassing the usual 2FA/MFA checks.
However, I now believe that was only possible because I was using a trusted device. I didn't want to experiment as a few times I had been redirected to a page that believed I was a bot and didn't want to risk any "suspicious activity" flags being logged against my account.
Give me ambiguity or give me something else.
