Who is your most underrated bassist?...

When it comes to Bee Gees, Beatles, Monkees… it seems to me there are men behind the curtain. Not in any way claiming it’s totally true… just somewhat skeptical the ones in the studio might not be who we’re told they are. I call BS Mo Gibb played bass on Bee Gee records. Could be wrong. I wouldn’t call skepticism slanderous.
Listen to those recordings and see if they sound like a 4001. That was the instrument that Maurice played. Not impossible to have a faceless studio musician use one, but my money's on Mr. Gibb.