FD is desperately trying to get EDO's performance up to decent levels so it can launch to console and avoid EDO being a net loss. You can most likely say goodbye to the graphics they rolled back. Yes, they lied about EDO to pump up presales. No, they aren't going to admit or even acknowledge it. For Stonks!
o7
Honestly, I don't think the atmospheric things they removed (if they
were intentionally removed) are particularly resource intensive, and removing them didn't result in any noticeable improvement in performance between alpha and launch.
Anecdotally, the real FPS killers seem to be the scatter rock system in boulder/bio-heavy areas (performance somewhat improved since launch), transparency shaders (mostly fixed), poor culling in interiors (unsure), NPCs/AI logic (better in some instances, got worse in others), and unexplained issues where FPS is fine at first and then crashes in the same area (may be related to AI).
Flying around above a planet, within the atmosphere but high enough that scatter rock issues didn't impact FPS, my performance has never been drastically worse than Horizons, even back in Alpha. Which makes me think the atmospheric effects, even the ones in Alpha, are/were quite resource inexpensive.
I have a hunch they've just broken them in an update, and it hasn't been fixed either because they can't work out how they've done it (spaghetti code), or it wasn't high priority because other things were higher on the issue tracker.