this list will be extremely biased towards prog and concept albums, beware all ye who enter. i'll primarily recommend albums, but also the most approachable song in each album to give a flavor of them if you don't have much time to waste.
1: Quiet World - Native Construct.
a wonderful extremely progressive metal concept album about the apotheosis of a mute man which is mistreated by the world; the story is as wonderful as the extremely complex music. try listening to "your familiar face" first.
2: Antimai - The Dear Hunter
prog rock concept album about the various circles of life in a dystopian future with a godlike ruler. each song sings from the POV of a member of a particular social caste; it is wonderful. try starting with "ring 1".
3: BILO IV - David Maxim Micic
suprise! another prog metal album with great sentiment and incredible mixing.
4: The Cocoon - Richard Henshall
the guitarist from haken! his solo work is incredible. start with "lunar room", spoken poetry with insanely progressive backing elevates it unreasonably. also just listen to everything ever made by Haken if you like prog metal, you won't regret it.
5: Presents by Harrison Fjord
the only non-metal adjacent album, this one is more of a callback and perfection of classical rock techniques. pink floyd, yes, and j-rock/j-pop influences make this a very interesting listen. start with "gbty".
that's it! if anyone gives these a listen and has thoughts (positive or negative), feel free to share ^v^