Add a Sequential Suffix Number

I don't know how to write code.
I figured out how to rename files with "date taken" exif.
Many files renamed have errors associated with same output file name.
I want to add a sequential suffix number but only for each file that will contain the same output name.
Again, preference is only for duplicate names and not for non duplicates

i.e. pattern output may look something like below upon renaming.

20210913_202606.jpg
20210913_202657.jpg
20210913_202657 1.jpg
20210913_202657 2.jpg
20210913_202713.jpg
20210913_202713 1.jpg
20210913_202719.jpg
20210913_202723.jpg

Reply to #1:
Hi,
have you tried changing the name collision rule? I think the rule that adds a number is what you are looking for.

https://i.postimg.cc/TPGH6LFC/img245.png

Otherwise, set the "Append pattern" rule with the following pattern: <Inc Nr> and a space as a separator.

https://i.postimg.cc/pVzvR86t/img246.png