The feature which makes making each page (or page range) into a separate PDF only allows adding the page number after the file name. It was added in the InDesign CC 13.1 update in March 2018. This feature isn't editable and what you wish is not an option.
I believe you'd have to use scripting or perhaps GREP on the exported files to change the order after you had exported the files.
No built-in way, that I'm aware of but you can fake it. (Does it have to be 3 digits?),
When you export your PDF, give it the file name of "0", then when you check "Create Separate PDF files", delete the underscore from in front of ^P then add your ACTUAL filename after it (e.g _filename). If you had pages 1 thru 99, you'd get: 001_filename.pdf through 099_filename.pdf. This won't work if you have more than 99 pages as that will force the appended number to three digits, so you would get 0001_filename.pdf thru 0100_filename.pdf but you see where I'm going with this. The other option is to invest in a batch filename renaming utility program to move your filenames around.