Yeah the miner hat I took from terraria and ninja set idea as well through the buffs are not related to terraria(I think)
Well assuming you have a mob farm and a gold farm you could use greed to gain loot fast and then repair the sword with gold, heck you can still use Mending+Unbreaking III+Looting III+Greed. It effectively turns ur sword into a farming tool that won't break, however I still don't think it's OP, here's why in order for Gold Sword to be better than any other sword at farming it needs ALL 3 of the enchantments(Mending+Unbreaking+Looting) if u miss a single one, a diamond sword might just be better with looting, and mending is pretty rare so u can't get a super looter sort by just finding 2 gold ore. And second and IMPORTANT reason, it's not great for damage, just for looting, u can't just explore with a gold sword or pvp with it, tho u can carry it as a 2nd option for looting purposes.
Guardian Armor could offer more protection, I'm just trying to balance things, trying to give more purposes to multiple armors, not make a single ultimate armor better than others but multiple armors better for different things that makes players actually question which to get. IMO Guardian Armor with Protection IV/Projectile Protection IV is pretty good in PVP with a speed II potion, the armor would hit players by itself and u just have to avoid them, may the players hit u they will also take damage, in addition in water u outright massacre any player lacking a trident. But yeah I guess u could buff it's armor to chain armor levels or maybe iron if it's not too broken.
Also yeah the ninja set could work similarly to invisibility, mobs detection radius would reduce to half at night, maybe actually turning you invisible to other players too, sees not very OP considering it's a frail armor and you stand no chance against netherite player if he finds u or tags u with a glow arrow.