Completely agree. For me the upbeat music really made the atmosphere of the original Colonization, and the later remake (based on Civ 4?) with its more downbeat soundtrack was much less enjoyable.
I've recently, by accident, found some of the tracks on Spotify:
Old Joe Clark - Fiddle Fiddle Fiddle: https://open.spotify.com/track/7HgGcA99K6wvF2nBwTY8nm?si=f-A...
Music for a found harmonium - Patrick Street: https://open.spotify.com/track/5vKaYFrSdHcFYsSz9gaDQg?si=pv-...
Here you go back to teenage years :D