Vet hard mode should drop gold jewelry.
No.
IF AT ALL, gold jewelry should only drop if a pledge was done in no death speed run hard mode.
It is more than doable, and it would still be farmed by many players with multiple characters.
I say it's fine as is.
Purple vs gold isn't that big a difference.
A better way would be to add them to trials.
Make trial leaderboards accommodate 1 place per account, not per character.
Then add gold dungeon and overland jewelry as leaderboard rewards.