Whew, I hear you. And it's not getting any easier with each passing year ...
Until the last few years, I was giggin on upright bass semi-regularly, and having the same issue. I bought one of these:
https://www.amazon.com/gp/product/B001Q3KT4M/
I removed the back part, set the seat nice and high, so I could sit back on the edge of it, but still be in more or less a standing position. Sometimes people would even say later, "Oh, I didn't even realize you were sitting down." I could even put a foot at a time up on the little footrest bar at the bottom to give my sole a break. Not sure if this would work for you, but might be worth a shot.