Sorry that didn’t help.
I’m not sure what else to suggest at this point, except to send feedback to Apple.
https://www.apple.com/feedback/
I will say that I’ve been using dual displays for years and never had a single issue maintaining window locations in any of the earlier OS X or macOS versions up until Catalina. At this point Catalina maintains the window location during a sleep/wake cycle, but rearranges them after a restart.
To be honest, I’m holding back at Catalina for now because there are too many reports (like yours) and it is bad enough to have to rearrange things after a restart.