Signal used to be the best but they dropped SMS/MMS ages ago, and group texts are historically awful over SMS/MMS, especially when one or more users in that group have iMessage. I would either switch to Signal and get your friends to Switch, use Fossify Messages (very basic SMS/MMS client), or deal with the shithole that is the G app suite. I’m on signal personally, I only use SMS for verification codes at this point.