I setup my system yesterday and ran into the 2FA issue with Xfinity. Like others who've posted before me, I entered the credentials, and it seemed like TVE was scanning the available channels. Instead it was bombarding my Xfinity account with 2FA requests, and I received dozens of codes texted to me.
I searched the forums and found I needed to either disable 2FA or create a sub-account without 2FA enabled. I chose the latter, but removing the source and re-inputting my credentials in TVE didn't stop the in progress scan with the 2FA account. I wound up restarting the machine to break the cycle, and now it works ok with my sub-account credentials.
Since this is a known issue and doesn't seem like it's on the radar to change, perhaps it would be useful to add text to each known 2FA provider with the same text that's used in the forum when users ask. For example, on the Xfinity credentials entry dialog, a Red "WARNING" with the following text: "TVE does not support two factor authentication (2FA). If your account currently uses 2FA, either change your account to remove 2FA or create a sub account (insert link here) without 2FA. If you skip this step, TVE will request multiple security codes from Xfinity and will possibly lock you out of your account." (or something like that).