Desync problems are from the server, not the flight model, on foot/rover/ships, the problem is the same.
You didnt get it. Current FM has accelerations in the excess of 20G in almost any direction (for light fighters). This kind of sudden movement cannot be tracked by a client-server architecture, especially a distributed one like SC has or is supposed to have (server meshing will solve NOTHING in that regard, actually, things will be worse since we have to account for inter-server communication on top of everything else). Remember games are stateful, and actor state has to be propagated to all other clients so they can update their own world, all of this under one "tick".
Manoeuver thrusters that are almost as powerful as main thrusters. Instant accelerations with infinite thruster availability (*). No moment of inertia. No mass either (ship movement is procedural, not calculated out of newtonian physics - hence why ships can be blown over by the wind or flipped over by small forces).
Ships move like dragging assets in a 3D editor, not like in a space sim. Go play KSP if you want to see how a space ship is supposed to move. (edit) and dont get me started on the atmo flight model.
(*) Also given their instant power, and huge amounts of it so they can immediately stabilize hundreds tons of metal just above a planet surface with a 1G gravity, their effect should be at least that of a Soyuz rocket every time they blast, instead the effect we get is that of a leaf blower lol.
"cartoonish / small light fighters 1v1" is just your opinion. A lot of players like the way ships fly now. 3 years ago, it was not the case.
Nope not just my opinion. Watch the latest video by FTR. A lot of people share that opinion but are silent as the very vocal, always screaming "I WANT A FPS IN SPACE" crowd have overtaken Spectrum for many years now (and because of them, we got the utter failure and waste of money that is Star Marines). FM is the most disappointing aspect of SC if we dont look at the sorry bugged state of the core engine. The only time they tried to make an actual step forward, and at least introduce a kinda realistic VTOL mode, all the light fighter "6DoF FPS" jocks who cant actually fly went "RRREEEEEEEEEEEEEEEEEe" and CiG took that back.