You are right with Tyson, those two beat a well beyond prime Tyson and those wins don't count for much. But I don't think that example crosses over to Stipe/Jon so much.
Both Williams and McBride were in their early 30s while Mike was 38 and 39 and had more than 20+ fights than both and had been fighting much longer. Stipe and Jon on the other hand are much closer. Stipe has 24 fights, Jon has 29, Stipe started in 2010 and Jon in 2008, so in terms of career and wear, they are very similar. Stipe actually has less fights, and less fight time. Jon is 5 years younger than Stipe, but more fights. Both guys have been pretty inactive with 2 fights since 2020.
With that said, Jon and Stipe are both in pretty much the same shape in terms of their prime, both are passed it. I don't think Jon any advantages here in that aspect.
I think fights like Yair/Penn, Craig/Shogun, Hall/Anderson, Mitrione/Fedor are more in line with your point.