There is no way to make PvP work properly in this game. The most obvious problem is that all weapons are balanced mostly to kill bosses with thousands of hitpoints in mind, not a player with 600 at most. And there is much more than that, which is why it's so limited in the first place.
If Summons targeted players, god damn that'd be so broken and annoying to play against. Imagine having to fight 6-10 completely unkillable enemies that don't stop attacking you while the summoner is chilling inside some blocks. If homing worked, those weapons that have it would be the only weapons everyone would ever use, and then matches would either a DPS test because no one misses their shots so there is barely any skill involved.
Imagine having to fight someone surrounded by walls, spamming a Megashark with Chlorophyte bullets into the air while a horde of unkillable Mini Twins back them up, how would you even approach that let alone find it fun to fight? And that's just early Pre-Plantera gear.
PvP is a fun thing you can do in Multiplayer, you'd have to do a lot of changes to make it work and it's just not worth it because I'm pretty sure it's at the bottom of things people do in this game.