The lack of bezel clicking is a broken/damaged click spring. That's a $15-$25 part that would take 1 minute to repair assuming you, or a watchmaker, had the proper pliers to remove the bezel assembly. This is what the click spring looks like:
You will see it has three pieces of metal that stick up. Those are what causes the bezel to click. I assume the metal tabs on the watch in question have been smashed down or broken off. That is super easy to fix by getting a new part. Esslinger sells them for $25.
The overall appearance of the bezel insert and the bezel frame are pretty rough. Is that what you want to look at? I wouldn't. A replacement from Omega will cost around $300. That includes a new bezel frame, bezel insert, and click spring. Omega sells them as a group. They do not sell individual parts. The good thing is that you can replace the bezel assembly without a service required. You could replace just insert with an aftermarket insert for $40-$50 but that would not include the bezel frame, and the one on this watch is in pretty rough shape.
You have not mentioned how the movement is running. Based on the watch condition I would guess not well. The case is in pretty rough shape, but on the plus side it's probably never been polished before. A full service from Omega would run $700, which would include a full service of the movement, restoring the case and bracelet, and replacing the hands, gaskets, and crowns. It does not include a new bezel.
So for $700 + $300 = $1,000 you could have a pretty much new looking watch.
I would find out how many links the bracelet currently has or how big a wrist it will currently fit. If it's too short, additional links will run $60ish from Omega and should be included in the calculation of value if it's too short for you wrist.
Edit - I see some extra links in one of the photos. Assuming you have an average size wrist you're probably fine without needing to buy more links.
So for $3,500 you could have a basically new watch. For something I consider every bit the equal rival of a Rolex Submariner (in terms of quality anyway), I think that's pretty reasonable.
My daily is the predecessor to this watch, the 2531.80 Brosnan Bond Seamaster. I've owned a Rolex 16610 Submariner, Rolex 116610 Submariner, Rolex 126710 GMT Batman, and Rolex 16710 GMT Pepsi, which are sold or I'm selling. I prefer the Seamaster, and it's not because of the price.