Although it’s true that you are increasing the attack surface when compared to locally stored OTP keys, in the context of OTPs, it doesn’t matter. It still is doing it’s job as the second factor of authentication. The password is something you know, and the OTP is something you have (your phone/SIM card).
I would argue it is much worse what 1Password and Bitwarden (and maybe others?) allows the users to do. Which is to have the both the password and the OTP generator inside the same vault. For all intents and purposes this becomes a single factor as both are now something you know (the password to your vault).