Textra is more feature rich but I had a problem setting custom notifications on Xiaomi phone so I switched to Chomp. Fun fact: both are developed by the same developer.
It is easy to turn off ads on Xiaomi. I am using Poco X3 pro for more than two years and never seen one.
Bigger problem with Xiaomi is media selector app and that they disable auto unlock Android feature (you can't unlock your phone automatically when at home or some BT device is detected).
Textra or Chomp SMS.
Textra is more feature rich but I had a problem setting custom notifications on Xiaomi phone so I switched to Chomp. Fun fact: both are developed by the same developer.