For me too, ejabberd is the admin-friendlier/lower-effort one. Being more "monolithic", your calls will work straight out of the box because it ships a turn server properly configured out of the box, manage certificates over ACME for you, etc. Prosody isn't bad but has a reputation of needing attention to be paid to which incompatible modules not to enable together and overall more protocol knowledge. Both will run on a first gen RPi effortlessly.