PoE 1 had a small but active PvP playerbase for a while with GGGs direct support / correspondance.
Sadly I think the sheer amount of almost endless possible builds in PoE (1 and 2) makes balancing PvP near-impossible <_<
Yeah, I totally understand why even Diablo 3 was impossible to balance for PvP, not sure why they lied in the marketing and showed us video about nice team vs team in unique arena... (PoE never lied about PvP.)
My solution is to have some moba on the side. (Examples: HotS, DotA, LoL.)
But to return to the main subject, Diablo 4 actually offers PvP zones with some concept of PvP - not only fight for the fight but - with sort of rewards. And while it is almost nothing, still more than PoE 2. (That still doesn't make D4 better in my eyes compared to PoE2 tho.)
Zknight