Good news - at least some progress. In terms of in sim settings, ULTRA or HIGH presets are good starting points. Make sure you don’t upscale (so keep render scale at no more than 100) and the Terrain LOD slider can be a big hit on FPS. Also experiment with the terrain pre caching setting - on ULTRA this can introduce stutters, especially when looking around.
I also have AI aircraft models set to generic, which I think helps a lot, and also if you are seeing poor performance at airports, turning down the static aircraft and vehicles will help.
Use developer mode to see where you are limited - CPU or GPU. I think the best approach is to try to find a point where you are on the cusp of being limited by one or the other. That way you are squeezing the most out of what hardware capability you’ve got. So if you are heavily GPU limited, that means that as well as turning down some GPU heavy settings, you can afford to turn up some CPU heavy settings, and vice versa - that way you can make sure both are working as hard as they can.
There are a lot of threads in the forum about improving performance - much is snake oil, but there can be some nuggets in there, and it is all so dependent on your system. The best thing to do is to try a few things and see what helps. As ever, try not to change too many things at once, or you won’t know what actually made the difference!
Good luck!