Hmm. I guess we need something to rebalance boon buffers then. There was one mmo called dragon nest where, devs were having problem where some support buff class outshined by other class. So the only thing they did was to give every support buff class the same duration, buff options and healing.
Every support has 30% max heal and if one support use their heal ability, others support get cooldown timer for balance ofc (since that mmo heal all the group).
Even the boon-like ability has same duration and will refresh other boons.
But one can hope