> The second factor does not have to be a second device. Like everything security, it’s what you’re protecting against.

It doesn't matter if you store your 2FA seed on a billboard or as a tattoo where the sun doesn't shine: 2FA means two factors. The definition doesn't change when your home setup's threat model doesn't call for 2FA and you thus decide to store two secrets in the same place (making a compromise of one necessarily a compromise of the other, thus 1FA)

Yes it depends on your treat model. But being defeated by one simple keylogger isn’t a risk I’m willing to take even at home.

You're onto something even banks don't seem to understand! The industry standard for doing financial transactions calls for 2FA but then they make a mobile app that can self-approve transactions. Yes, using only one mobile device is 1FA, just like using one desktop only, but people generally consider mobile OSes safer because the permission model and process isolation is on a whole other level