For explicit hobby use, I prefer tinkering with software common at the time these systems were new. Then I get to play with different UI and some apps/games/peripherals which do not work with emulators, or are better on the real thing.
"Newer old hardware" might be different, but it's also less likely to need special distros. I have a 2013 Macbook Air running Sonoma thanks to Open Core Legacy Patcher. Everything works fine with patched stock OS. But practicality of Pentium 4 is a stretch.