I had an early concept that was similar but scrapped it for the sigils idea as I felt it was more challenging as relics have already been used twice and many are experts at using them

It would more of a agility mechanic requiring you to gather the item to instigate boss damage. All while you are navigating the arena the boss is an obstacle of damage. Then you can deal damage sort of like times vengeance. But their isn't a relic collecting the items just activates the buff.

There's endless possibilities for raid ideas and yours sounds rather interesting as I suggested it was rather fun project and I'd recommend you flesh it out and post it