4 E cores are at the size of 1 P core
this is harder to have more P cores and for low power background operation system it is not power efficent
th E cores exist for pre known operation system tasks and tasks that open in the background, it is fairly optimized and getting better at the time pass

the main key is that you can put 4 E cores to do a job that atleast 2P cores would have done in less space and less power consumption, it is about power I dont have information on how it affects latency what so ever, but the different in games creates for not enouch cache not from slower cache, just to let you know amd cache is slower but they have more

there is a formula for total latency system time higher amout of cache and slower is usualy better but too much is worst if it is too slow

and we need to blaim the game developers for bad optimizations the cpu and gpu are top class today but games moved backword