Thing is - this RPG genre heritage, you will gain advantage when you do participate in all of the content. You PvP and PvE you will have advantage on anyone who only does one of these. You farm M+? you will have advantage over people who only do one a week.
I hated agility leveling in Runescape, but I had to do it. Same in Lineage. Different activities fall perfectly inline where you do game modes which do not influence one another. LoL - ARAM/Twisted/Classic/dominion or whatever that was. CoD - zombie, campaign, TD and so on. It's a short game where you choose to play that only.
WoW was the closest to this in legion with BG's being template stats. It could have been the same in TBC with resilience gear, but then again, you meet people out in the world who don't play that mode and you have advantage over them. The only way to make people to not have to do something - not let them interact with players who do that activity remove any influence that their uncommon activities have (give them templates) and only leave the common things (talents/spells)