Hello PhilNitram,
I own both Galaxy S7 (version e-2.5-s stable) and Galaxy S10e (version e-2.5-t dev).
It is true that the S7 has an echo problem (especially when loudspeaker on).
This is no problem of this sort with my S10e (and I use it very often with loudspeaker on).
I hope my answer will help you…