Re: 2FA is so poorly supported
PayPal make it difficult, but it is possible to use 2FA on mobile.
Firstly, you have to use device-based 2FA rather than SMS. You can get a physical key, but I use the VIP Access mobile app on iOS. There are details (with slightly out-of-date screenshots) at https://www.paypal-community.com/t5/Tips-from-Moderators/PayPal-Security-Key/td-p/433633 .
Then, when using it on mobile, you have to enter your password and then the 6 digit code from the device or app **appended** onto the end of the password.
So if your password was 'fasd91"kfasP' and the 6 digit code was '913763' you'd type 'fasd91"kfasP913763' as your password.