Mixed can be fun, if the level of the players are somewhat similar.
Nobody needs to blast the ball, but they do need to hit low, up the middle, and dipping shots.
Returns of big serves can be lobs DTL, or short volley angles.
Serves only need to get to the stronger player's weaker side, whether weak in consistency or weak in pure power.
I play some version of mixed at least 1 out of 3 days. Usually in some version of 3.8-4.2 tennis levels, if such a thing exists.