I have exactly the same problem. Your log file looks just like mine. The last time I used the 2019 business program in July it worked just fine. Now it won't open. I installed the 2020 HRBlock Business program today and it will not open last year's data base. Says the the files are in use by another program and to close it. But no such situation; there is no other program running. I even rebooted to be sure nothing is open. No luck.
Did you ever get the problem resolved? The last message says to uninstall HRBlock then reinstall. Did that work?
This is where I was also ‘stuck’ with 2019. I solved 2019 issue by following the steps in my previous post to uninstall all DEC2020 Microsoft WIN10 updates. Then reboot. Then 2019 ‘magically’ worked again. Good luck and reply if you get stuck!