Definitely wear the leather armor for now. Leather armor +2 is better than chain mail +0. I would try to identify the plates. If they are +2 dump upgrade scrolls into them so that you can wear them with 15 strength and then do so when you reach that. Or try to reach the smith and upgrade the armor with his quest reward.
What wand did you get from the wandmaker? My usual approach is to imbue my staff with that and then use it as my main weapon and upgrade it further.
Got wand of corruption from Wanamaker. I was gonna wear the leather going forward. The chain has viscosity and that helped me weather tengu traps. And plate armor is no upgrades
You probably just want to get heal pots from f11 shop, put your 4 sou into that sword and armor to get them both to +3, so you can wear them both with 16 str. To survive until you get both pos from f11-14, put 2 or 3 sou into your evasion ring to boost your ehp. With t5 weapon and armor and chains, the caves boss should be a breeze, and you can snowball the run to ascension