Spent two and a half hours trying to simply get CGIs working on a RedHat 8 system. I've done this a zillion times on various Unix platforms.
Turns out suEXEC is on by default. Since I never use it, it probably wasn't configured as I needed it or my CGIs weren't using it right. Turned it off and everything works.
Not what I needed, returning from vacation with a pile of work to do.