Renaming file having same "Title"

I have near about 20000 songs and some songs have same ‘title’. When I try to convert ‘title’ to filename, sometimes it says – “cannot rename filename as that file already exists”. Can I use some command or script where if that filename already exists the script automatically increments the filename by digit 01,02 etc

No.
You would have to think about data that makes the file unique.
E.g. a grouping files in sub-folders could lead to unique filenames in those folders (20000 files in the same folder is quite a lot)
Or finding out, if those tracks are really the same or they deserve a little amendment like "Maxi" or "live".
If those tracks are really the same, then it might be an idea to delete some of the duplicates.
You can find out the untreated files with a filter:
"$if($eql(%_filename%,%title%),1,0)" IS 0