No, you're not the only one. Odyssey performs very poorly, even on RTX 30*0 series cards.
Performance hasn't changed significantly since the alpha. I accepted the poor performance on the alpha, but for a live release it's a bit of a joke.
Meanwhile I'm happy that I can play on 1440p again as opposed to having horrible performance even on 1080p as in the alpha.
Sure, I'm not getting the 100+ frames per second I used to have on that resolution in Horizons, but for me it's not anywhere near alpha levels bad (now its near 60fps on average, which I personally consider playable).
I also haven't reset my graphics overrides yet that I still had in place from Horizons, I had some issues with some of those settings during the alpha as well so maybe that may still improve something (or not). So I wouldn't say there isn't a difference in performance for me compared to Horizons, but still notably better performance for me than the alpha had.
FYI:
CPU: AMD 2700X (not OCed or boosted)
GPU: AMD RX 5600XT 6GB (on latest 21.5.2 drivers, not OCed)
Mem: 32GB DDR4 3200 (clocked to 3000)