Pixel Dungeon

I would get to an alchemy pot to see what trinkets I get. Then imbue your staff with one of the wands you have and use at least 4 SoU on it. What wand you imbue is dependant on your play style/trinket. If you have 14str I would just try on the chainmail and hope it isn't cursed, it might be upgraded which would help. With a decent staff, 2 heal pots, and 2 blink stones from that teleport scroll, you should be able to kill tengu.

I would power through until you do the wand ingredient quest, them decide which of your wands you want to infuse. You want pure damage in you staff, so unless they offer disintegrate the wand of light might be your best bet.

You need to decide if you want to go battle mage or warlock. If battle mage, pump all your upgrades into your staff. If warlock, pump it into the ring if wealth and grind until you get good equipment.

Just my opinion though, I'm not a pro or anything. It seems you have a really decent seed though. Definitely remember to use your bandits armband to blind and kite enemies.

Oh, and what was offered for the arcane resin or whatever the orange fuzz is called?

The chains and rof will help a ton. Personally, I don't like dumping upgrades into scale armor since you get more bang for your buck with plate, and now you need to decide if you are willing to stick with your scale for the rest of the run or not. At +5 it shouldn't become a problem until the last few floors/eye boss fight. I don't like prismatic in the staff since most of the benefit from prismatic is finding traps, secrets, and blinding ranged enemies, which don't happen often enough to justify getting 8+ charges of it at a time, so I would use lightning. Keeping magic missile is pointless rn, since it doesn't give you more wards or much damage with prismatic, and the extra lightning damage would be easier to get if you just put the lightning wand into the staff.

I'd equip the chain mail armor. Even in the worst case, is better than the one you have equipped right now. Then I'd throw the broken staff directly above the upwards stairs, so on my way back to the surface with the Amulet of Yendor I don't forget to pick it up (so I can get the You made it too advancement) and I get an extra inventory slot for the rest of the run. I wouldn't worry about the scale armor, as it'd have to be a +3 for it to be usable at this point in the story (I think it was a 5% to 10.5% chance depending on where you found it, a bet) unless the mage quest is the the Rottenberry one, then you have the choice to (first find a blandfruit) cook it with a blandfruit to get an extra point of strength, if mage's staffs don't convince you, then the scale armor would just have to ve +1 or more for you to be able to use it.

Also, if that mail armor isn't upgraded, Tengu will kill you. You might need more mobility too for the badder bosses Tengu, he sometimes throws unavoidable attacks at you unless Ring of Haste +2 or Ethereal Chains (and by sometimes I mean all the time, and by attacks I mean the fire gas one. Maybe try to get brimstone glyph. If you get hit by the fire gas while you are wearing an armor with the brimstone glyph, you won't be eligible for the Gotcha badge, btw)

Then I'd choose warlock because I'd rather restart the run than being forced to use the staff as my melee weapon.

Then I'd search for a plate armor before I get killed by the mines' enemies (or, if the scales is good enough, I might get to goblin city, then same applies) and bump my upgrades into it. And then I'd just win, if I don't do anything stupid near the stupid floating eyes.

I'd equip the chains, imbue the staff with lightning and pump every upgrade scroll into it.

With any luck the chains are at least +1 and the staff's damage output is enough to make short work of Tengu.

Then I'd go Warlock because it's so much fun to zap multiple enemies and your wraiths and get the mark on all of them so that you even get health when enemies attack the wraiths.

Edit: Equip the shield for Tengu as well for additional defense.