If you're going to be in Coil, and Primals, I say Parry. Even if the return is insignificant on its own, remember we have 13 pieces of gear, don't shrug something off just cause you don't see results.

I did my Nexus parry/det, in contrast to the ilv135 parry/crit from FCoB.

Idk why people go crit/det on tank relics. I feel these people are frustrated about not being DPS and being jelly of them but meh. Our role is keeping aggro and surviving enemy attacks, and the only stat that helps in that is parry.

If you're doing relic w/o progression in mind, feel free to go acc/det/crit.