To be honest, I can't see you can describe many 'luxury' dive watches as 'serious'.
You mention the Submariner repeatedly, but what can it do that a Sinn or a Pelagos, for example, doesn't do just as well?
The Ploprof reissue is not intended to be the tool it was, no one NEEDS a Ploprof these days (actually it turned out they never did...), it's the epitome of a 'luxury'.
Omega and Rolex are in the market for luxury goods, not tools, these days.
If you want a 'serious dive watch', you need to look away from luxury brands, imo.
M