My ‘20 gasser was the same way. That and the trans were the biggest reasons I got rid of it.Have they put more cushion on the seats compared to a 21'? I can handle about 3 hours in mine before I have to get out. Until I added a piece of foam topper for long trips.
Love the seats in my ‘03. Although the drivers cushion is about due for a replacement.
My buddy that is a gm tech says he’s had lots of trans pump seals fail in the 10 speeds.