Obenaufs is a bit difficult to work with, and it is always better to apply products sparingly. You can always apply another coat later, and it doesn't hurt to test products in obscure spots first, either.
@Belicious has used it more often than me so she can better advise you. I've only used it a few times when I wanted to darken a bag a little - but I don't know how it would react with those damaged areas on your bag.
There may be another option. A good professional leather worker/shoe repair/cobbler can spot-dye a bag. I've only done that once. I picked up a mahogany Patricia's Legacy bag cheap but it was in bad shape. There was a rip where the flap attached to the bag and the finish was damaged right on the front flap.
I took it to a good local cobbler and he repaired the rip and fixed the finish and spot-dyed the area, see pics below. I don't remember how much it cost but it wasn't bad, maybe $20 or $25, and I was pleased with the repairs.
Nowadays I would probably have left this one on the shelf, but I am glad that I was able to save this lovely bag!
Before Repair:
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After Professional Repair:
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