Elite dangerous DLCs. quite confused.

Sorry for being a broken record. but here i am ;D

I've like space game like Homeworld, Freelancer, Freespace, X4, Everspace.

I did some research since i am planning on buying ED on steam, then i saw Odyssey expansion.. so here's some questions i gotta ask before buying.

1. If i play the Odyssey as a start, will i still get to enjoy the base game (horizons and down) to it's fullest along with the expansion? or Odyssey is a different expansion?
2. Assuming i bought the DLC as well and i chose to play Horizons only (is this possible?), do i get to enjoy the graphical improvements and exploration updates Odyssey has in a horizon only gameplay?
3. Since this has a online feature, how does the DLC affect my account? do i get lobbied in a odyssey players. and if i go on only horizon gameplay, i will get lobbied in horizon players, right?
4. Is it worth playing on the Odyssey now? i heard it was buggy as hell :O
5. If No.4 is a NO and i started playing a horizons only gameplay, then became a YES later, can i continue my gameplay on Odyssey, or do i have to start all over?

I'm buying the game since i like the space part, and on foot-explorations(DLC) and not the FPS part(why…), though the graphical improvements piqued my interest.

I've been yearning for this game since 2015, and now i got the hardware to play it (r7 4800H, rtx3050, 16GB RAM).

Thank you 🙂