I am teaching students with special needs virtually, due to COVID. Many of the educational activities I am using require Adobe Flash Player. I'm assuming these will all be inaccessible after January 12, unless all of the various providers/developers transfer their content to another format. (I hope I'm using the correct terminology.) I feel as if a great chasm of the unknown is opening, and I am standing on the edge with no idea what to do. Any suggestions?
Yes, these activities will be closing down on January 12. There have been three years for the creators of these educational tools to make new ones that don't need Flash (your terminology is good) Have you checked with the creators of these activities and tools? They were already of very limited use for general educational use, and have been for many years, since Flash doesn't run on the iPhones, iPads and Android devices most students are likely to have. My suggestion is to look for discussions in forums devoted to the educational field you work - you are not alone, and I would hope some people have been working towards solutions, not just waiting for the end to come.
The Adobe Education Exchange is a community resource for educators to publish and share educational content with other educators. There's a lot of K12 content for a variety of subjects. It might be a useful resource for finding some replacement content.
Talk to fellow teachers.