You should use the numeric suffix on the 1st file as well, so it has a 0 or a 1 at the end. Otherwise, it will always be captured as the last item.
Also, preferably use padded suffixes, so that if there's less than 100 files, use 01, 02, 03, <...>, 11, 12, 13, etc. If there's more than 100, pad it with leading zeros so that it has 3 digits. This way they will be sorted properly.
To pad text, use the Pad text action on your suffix.
-------------------------------------------------------------------------
If I have answered your question, please mark it as the preferred solution. If you like my response, please give it a Thumbs Up.
I also provide paid consultancy and development services using Power Automate. If you're interested, DM me and we can discuss it.