What about instead of boost for gold, there will be only boost for boost? like:
raid for arena
arena for m+
m+ for raid
raid for pet battle
pet battle for trasmorun loot
mount for achievemnt
achievement for arena...
Or any other combination where player A got boosted and pay player B with a different boost
(yeah i'm an one of that old boomer that boosted pandaria challenge for gladiator title, or trade a full siege of orgrimmar ex hc for a full pvp guild and they boost all our raider to gladiator)
That was super sweet