Hi @bblanco
Yes, configuring an authenticator is still required. MFA is now mandatory for all admin accounts. See this Deprecation of Strong Authentication on Admin Step-Up and MFA set up for IDN Admin account
While you may not need to log in through the interactive UI often, you would still need to authenticate to create PATs and/or to create or update saved search queries and subscriptions etc. Setting up an authenticator provides an added layer of protection to the service account.