It's surprised me that there has been no evaluation of the termination of Adobe Flash on this forum. I've come across this topic on another forum where the implications for security camera were discussed. Basically, Flash is full of security holes and has been flagged for discontinuation for several years. There does not appear to be anything else to do the same job. Adobe made the situation clear enough and Microsoft are fully supporting them.
Microsoft and Adobe intend to remove Flash completely. There is a Windows 10 update which stops Flash running on a computer which cannot be reversed. The only way round is you have made an earlier restore point or do a full reinstall of Windows 10 avoiding the update. I'd say that you need to junk the software that requires Flash and move on. I have computers running Windows 10 and XP. I am no longer able to view my security camera viewing feed via any internet browser.
So no I don't think there is any alternative.