I'm playing through ToD right now, feels somewhat important if you want to get some of the references (the origin of the dimensionator, Rusty Pete references etc.)
The estetic and general "this is next-gen!" vibe is also very reminiscent of ToD. I'm still genuienly impressed by it!
Thinking of finishing ACiT and Into the Nexus, but I'd have to buy the latter... I think I'd be fine with skipping QFB though.
Unfortunately, I barely played the original trilogy... (Finished the PS4 remake of the first game though... Yes, I know, I know...).