A guy in another thread had a problem running Poser Debut for the same reason. The reality is that Flash is no longer being supported because it's a serious malware threat now, with many backdoors. Even Apple has got rid of it in Safari this year, and no software going forward will have it. Windows 10 defender won't even let you install many of the Flash installers or any app containing Flash now. Adobe has urged everyone to disable Flash, and Google Chrome has Flash addon disabled by default. You have to manually enable it to run Flash-enabled web content or pages.

So, I think your only choice, if you really want to run something with flash is to get yourself an old, outdated computer that is not connected to the internet and using an older OS and just install it there. You can find an old Windows Vista system for next to nothing these days, or even something with Windows 7. Just don't connect it to the internet.