Yeah, I had that problem too - think I needed to get rid of 10.0 & 10.5 but not older. Unlike back then I’m installing the older ones after installing 11, not years earlier like on the old PC.
I had been sitting on a bunch older Project that needed to have their VSTi’s rendered. Did I do that when I had a system all set up to do exactly that? No of course not - the procrastination is strong in this one. But then the PC died & I learned a lesson - so trying to get to a state where that rendering can happen.