Yeah it gets harder to remember what was called what at the split . I had took it as horizons was consoles , live 4.0 was Odyssey light and Odyssey was the full. I may just start calling it Consoles and Odyssey now.
Yeah I think that's more or less it...
Horizons was the v2.0 paid expansion, initially PC-only and then later the consoles were introduced.
All platforms went thru the v3.0 Beyond free updates "together".
v4.0 Odyssey paid expansion released to PCs only. Horizons features were rolled into the v4.0 game client as the new "base game", so all PC users have access to the v4.0+ galaxy whether they bought Odyssey or not. Odyssey owners have more content, but the game engine and BGS is shared between all v4.0+ users.
FD later announced consoles were done, leaving them frozen at v3.8, which got the "legacy Horizons" label. Consoles and PCs can still play in the dead-end v3.8 multiverse variant lol if they want.