This bag is in decent shape for its age, and "pre-Kelly" Kellys are harder and harder to find (I have one from 1952).
This is Box leather (named after Joseph Box).
Apres-vente will be thrilled to service it and it will cost around 350 in USD or euro.
A handle replacement would easily be 3x that.
The bad: that cracking in the leather cannot be fixed.
Overall if you do not actually want a funky/very vintage look to your bag, this is not the bag for you. FWIW, although I love my 1952 Kelly (which is in much better shape than this bag), I only carry it when I specifically want that vintage/cool/indie look. Doesn't sound like that's what you want from a Kelly.
ETA: Resellers will charge almost anything for an Hermes B or K no matter what shape it's in or how old it is, in the current market. 3600€ is really high for this, but I definitely see many bags priced this way. I paid USD $1500 for my '52 in a much lower market, but mine had a large pen mark on the front (which I was able to remove). Waiting for the market to soften is an option.