Recent T-mobile account hack left me with a compromised account affecting 2 brand new

Feb 17, 2023
Suspicous activity on one phone but not the second (better) phone.

Need advice on what to do beyond changing sim cards and setting up new account. Hard, Factory or Soft resets? Have VPN, pw manager. 2FA and T mobile supplied security software (name brand but probably stripped down).

Not sure how deep intrusion is, but a new device name (not the one I assigned during setup) associated with my new device Google acct is a red flag for one or more hidden profiles used to gain control over the phone remotely.