I think you covered it pretty well. Blackgaze and OSDM revival seem like the defining tastes right now. There's been an upswing in free jazz influence as well, I think, and I feel like dissonance is experiencing a surge in both.
Osdm is a very saturated genre at the moment and spectacular quality isnt always needed to become popular. 20 buck spin maybe is the best example as they have a cult following them.
Maybe blackgaze, post-black, hipster and stuff like that which was very popular then has lost either quality or interest or both. Raw black metal has become more popular, thats more of a trend than an increase in quality (imo).
Here's my list of symphonic metal albums from the bands that I know of, this list is defined by the terms of "atmospheric/bombastic sounding". This is my first time of making list on this site, so some of this might not make any sense as I'm still a bit confused myself as well, and I don't really prefer to see these in particular orders.
This list can be changed over the time and I might add more albums later on.