Repairing large ammounts of items is boring and repetitive for various reasons. It involves lots of sorting items, checking their condition and remembering which items were the ones that needed repairs and which ones were the ones that were supposed to be used for repair. In addition to picking up and dropping items and running around in base from stack to carpet.
Scrap the current condition transfering method. Make it simple and fast:
You need a tool in hand plus the materials needed to craft the repairable item. After that you can just press 8 and click on item on ground, inventory or container.
A special "item awareness" could be included when you have the repair crosshair selected and pointed on item. It would show what item is in question and what's its condition. Like this:
Same in inventory:
Succesful repair shouldn't close inventory screen.
Normal tool could repair first and second tier items without losing much durability. When fixing 3rd tier, it would break down faster. Super tool kit could fix everything and endure very long.
Now that you also need to have the items needed to craft the item in your inventory, the deal here would be that these items would randomly be spent upon repairing. The less the armor is broken, the less chance you have to spend any mats. So if armor is broken at 90%/100%, your chance to spend a piece of material would be 10%. It would add some twist to the boring life of a mechanic without making repairing free.
If repair skill is supposed to serve a role here, whatever - people just get 300 repair alt. So it's all the same what it does.
Super tool kit should be craftable, farmable and should spawn in shops.
If armor is beyond repair, it should turn into materials as if it was scienced. So basically you can science armors by punching people who wear them. The materials received should be minimal however.
Overall repairing will always be a boring task that hardly adds nothing interesting to the game except another time sink passed in a cave. It could be more exciting but that would require some other game mechanics to change. So much about it.