If we analyze the error from backup command. It is complaining about log file. So I thought how about trying to attach just MDF file but it failed.
sp_attach_single_file_db @dbname = '[TDEDisabling]', @physname = 'J:\Backups\TDEDisabling.mdf'
Msg 33111, Level 16, State 3, Line 1
Cannot find server certificate with thumbprint '0xBB1B0816079C10A6342683443A8E576196EFBE73'.
Msg 1813, Level 16, State 2, Line 1
Could not open new database '[TDEDisabling]'. CREATE DATABASE is aborted.