So I've been flying the Anaconda since Odyssey released. Some settlements do not have a large enough landing pad for me, some do. In those that don't, my FPS can be "decent", ranging from 30-60. In those that do, it can get abysmal, around 15-20 FPS. I simply assumed it's solely due to the settlements being larger, more stuff to render etc.
I was wrong. I just pulled up to a huge settlement and had a little brain fart. I landed without requesting docking permission. It slipped my mind. I got out, did some stuff in the settlement with the FPS around 45. Mid-way through, I realized I parked too far, went back to the ship and requested proper landing permission, then docked. As soon as I got out my FPS was 15 and pretty much stayed that way.
I tested this 3 times, and each time if I don't dock but park somewhere on the side, my FPS is a lot higher. I don't know why, but Odyssey did something similarly weird before the second hotfix. Upon leaving the concourse and returning to my ship, the FPS would for some reason go down the tubes and into single digits. So it's doing a lot of weird stuff I don't understand, but I hope this helps someone with their performance.