Instead of rendering the ESP everywhere on the map at all time. Why not include a ESP distance limit by in game meters. So the ESP will only render within 60 meters, 150, or 300 meters out from your character position. Might even help a bit in the performance area.
Alternatively... There used to be an optimization technique in games where areas were divided into zones linked by portals. The assumption being by exploiting these zones, you could optimize resource usage. You had resources for your current zone loaded, resources for neighboring zones in hot storage, compressed in RAM, and zones one or more hops away unloaded and waiting on disk. The assumption being it would take a player a minimum of a couple of seconds to traverse/observe a zone that was more than one hop away, allowing the game engine to efficiently load/unload resources as the player was traversing zone boundaries. If something like this exists in the frostbite engine, it'd be neat to allow an option to only render ESP for players from the current and neighboring zones.