The problem is with the BUSINESS module only, not the Premium (personal) program. They are completely separate programs written by different teams using different database software. Unfortunately the Installer program forces you to install or reinstall both, or it will reinstall the Premium and delete the Business, so you have to start all over again. I wish the two programs had separate installers, but that would make way too much sense.
Apparently Windows changed the way encryption works in their Framework module, and every time Windows has a major monthly update (2nd Tues of the month?), something changes in Framework that makes H&R Business databases inaccessible. If your Business program is working, you can Pause Windows Updates (not Defender security updates) for up to 35 days if your software is working, and try to finish your work before the next update. Backup your work.
Note that if you can fully open the Business program and restore the database properly, you have to select Open Saved Return from the File menu to see the list of prior returns you've created.
If following the fix instructions previously posted (re: the DataStore and RestoreDatabase files) carefully doesn't work after multiple attempts, you can uninstall, cold boot, then reinstall software. H&R says uninstalling software does NOT delete the returns. But beware, after a few installations, H&R will say you've exceeded your downloads, so you'll need to request a new download link from them. Good luck contacting them, wait times are LONG. You can try the Chat feature in the Personal (Premium) module, but expect to wait. Be sure to tell them you're having problems with the BUSINESS software (not Premium). Always reboot after uninstalling or reinstalling software, and clear your browser cache.