Gem game idea
For a gem game what if you make it like a raid boss battle where it's health is the gem pot. Each time you damage it you gain x amount of gems and last hit will double or give a certain % of gems that player earned so no one just waits for last hit doing nothing. Dying either has timer or loses maybe 1-10% of gems earned so it's not a big loss but still discourages berserkers going in and dying constantly for max hits. Also so not everyone is just ganging up on one boss you could split it into multiple bosses that are highlighted or you could just make it a giant and has knockback resistance. As for weapons everyone gets a sword only but there are a few bows in boxes hidden around the map with limited ammo that do more dmg like if sword did 1dmg than a bow would do 5-10 dmg to reward players for searching.