I may have misread the tone, but Rolex's release regarding the shortage rang with a certain amount of contempt for consumers.  Not unheard of when interacting with luxury markets, but by no means is it the norm.  Swing through an Omega AD, and they just might pour you a glass of champagne -- swing through a Rolex AD, and ... well .. you already know.  

I do still want to add a precious metal datejust to my collection  (they're really f****ng classy, sorry), but it has been pushed wayyyyyy doooowwwwwn the list for me.  

There are some truly beautiful pieces from Omega that are eminently available, and Zenith's El Primero is a technical achievement without peer.  Its true, I lose out on the status that comes from wearing that crown, but most people aren't going to notice that anyway.  I wear watches because they bring me joy.  The intersection of careful design and functionality crammed (tastefully) onto the real-estate of my wrist.  It's jewelry with history.  Rolex's current state lacks that joy.  Sure they'll still mumble on about heritage and uncompromising quality, but nothing that they've done has discouraged the grotesque grey market; there's nothing dignified about that particular feeding frenzy.

TLDR:  Zenith and Omega and Ball and Nomos and JLC and Blancpain and Cartier and many others are producing exquisite watches.  Exquisite watches that can be purchased without trial or excessive blood loss.    

The Ball Trainmaster Standard Time has a gorgeous enamel dial and tritium tubes for illumination.  Doesn't quite hit the 2.5k target, but it'd expand your collection without making any of your current pieces redundant.

I was thining "Hydroconquest" before I got to your list of candidates.  I'll probably take some heat for the following statement:  I think Longines Hydroconquest is a more attractive watch than the submariner.  It is absolutely beautiful.  Longines has really been striking gold lately.  

If you're willing to take a couple steps away from divers, the Tudor 1926 is a gorgeous watch that I could imagine gracing the wrist of Bond villain.  Only a single step away from divers is the Longines Conquest, another beautiful watch.  You mentioned that none of the candidates in the list feel "quite right", so maybe something that is similar but not quite a diver is what will scratch the itch you're feeling.  :-)

If the diver thing is non-negotiable, two other options that may fit the bill are are Aquascaphe by Baltic or the D7 Swiss Atlantic by VAER.  These two are significantly cheaper than the $2k mark, but they're still fantastic dive watches.

The $2k field may not be as well-populated as the sub-500 field, but there are still countless options.  Good luck in your search!

I really enjoy "playing dressup" with my watches, so watches with integrated bracelets aren't a real high-priority.  If someone put a gun to my head and said I had to buy one of these, I'd go with the Aikon though (in quartz).  Why quartz?  I'd hate to sink cash into servicing a watch I rarely wear.  :-)  Why Aikon over PRX?  The design of the PRX really leans-in t the fact that the bracelet is integrated.

Zenith's defy series is absolutely amazing.

The Longines Conquest is a fantastic GADA (Go Anywhere Do Anything) watch.  Moving up the ladder just a tiny bit is the Omega Aquaterra, another fantastic piece.

Grand Seikos are gorgeous watches, I don't have a single negative thing to say about them.  However, I'd caution against buying any watch in lieu of another.  If the Bregeut is the watch that makes you catch your breath and your pulse race, don't buy another watch hoping that it'll "scratch the itch."  There's a good chance that it won't, and then you'll have a (still beautiful) Grand Seiko that stirs a little resentment in you -- which is a really weird thought.  

If landing the GS is just single stop on your roadmap to the "Big One" go ahead and pull that trigger.  I don't think you'll ever regret having a Grand Seiko in addition to the Bregeut.

I feel fortunate that my grail is the Ressence Type 3 -- there aren't really any other watches out there that borrow enough design cues from it to potentially serve as a substitute.