In general, playing at the net feels really weird and seems to be mostly determined by your net presence stat. I think one gameplay mechanic that is missing is the split step. It could be used to discourage players from just holding the run/sprint direction all the time and reward players for being patient and reacting to your opponents strokes. One implementation could be that holding a neutral direction at the time of your opponents contact (or something like that) could initiate a little split step animation and give a boost to acceleration/change of direction. Maybe you could give a penalty to breath/endurance stats if the player attempts to change direction at high speed without a split step. This seems especially important for players trying to serve and volley as it just feels very uncoordinated today.
One other bit of feedback as a PS5 player, overall the gameplay is really good but there isn't enough content to make it worth playing for more than a few hours. It just feels like a grind trying to get points and there doesn't feel like there is a sense of progression.