2FA at organization level only with Duo

Hi! Does anyone know why I can only enforce 2FA in my organization (Teams plan) with Duo? Shouldn’t I be able to enforce it with any available authenticator app as LastPass does?. I don’t see the advantages (or I don’t want them) of using Duo over more traditional methods. Furthermore, once we go over 10 users on Duo it stops being a free solution, so I’ll need to pay Bitwarden plus Duo.