Prevent "is this you" popup on my phone There's a Google account I share with others which I use as an oversight account, to be the maintainer of several shared Google Drive folders. I share this account with other members of a small team, which occasionally gets new members and has old members leaving.

Whenever a new team member tries to login on this shared account, one of the members who already had the account logged in on their phone gets a confirmation-popup which they have to confirm in order to be able to login on the account. I've never set up any 2FA or anything in my Google account, and I've not set up a recovery phone nor set up my phone to sign in.

So basically nothing about my phone should be specific to my phone, and Google shouldn't even try to ask me if it's me trying to sign in. This leads me to my question: how do I prevent this 2FA-like system from requiring me to confirm anything at all on my phone whenever someone logs in from a new computer?
No. There's no way you can prevent it. It's a security feature implemented by Google as pointed out in comment

If security can be relaxed there is no security

In your case with people joining in and leaving all the more reason - think of it as you are running a small company with employees using a common mail account - you wouldn't want unauthorised access

That it's a low value account to you is not relevant given that it's your account and Google security policy rightly does this