I wouldn’t call it underappreciated since it was well received in its time, but Star Trek: Judgment Rites was amazing.
I wish there would be more narrative focused Star Trek games like that. Either a Disco Elysium style non-combat focused RPG or a modern adventure game.
A Disco Elysium style Trek game would be killer. Make me make ethical decisions about other species, decide if I want to be a Starfleet or a Maquis, and make awkward conversation with my superior officer that gets me reassigned to Delta Shift cleaning the Holodecks, and seriously reconsider my life.
It is a 90s point and click adventure, having played this and the original 25th anniversary one recently I think it holds up well.
One thing that is nice about Judgement Rites is you can skip the ship battles if they aren’t your thing. They are fun but can but super frustrating.
Also check out A Final Unity which is newer with the TNG cast but I think still really looks great and the entire cast voiced the characters so it is almost like a mini season of the show.
It depends on how familiar you are with old point and click games. If you aren’t used to them, it can be quite frustrating, but even then I think it would be enjoyable if you use a guide to unblock yourself when you get stuck.
At the very least, the music is great and the writing is full of great jokes and also some pretty compelling sci-fi scenarios that would have fit perfectly in the series. If point and click adventure games aren’t your speed, find a walkthrough (theynarent hard to find online) and refer to it whenever you’re stuck.