The only thing Plex needs from a show is season# and episode#
Here is one example I gave many moons ago to show how lenient Plex can be.
! \Cheers (1982)\Season 01\He said he was not there yesterday; however, many people saw him there -
01x01
- Some Title Name.avi
! \Cheers (1982)\Season 01\I am never at home on Sundays -Season-01xEpisode-02
- Some Title Name.avi
! \Cheers (1982)\Season 01\I checked to make sure that he was still alive -Season01xEpisode03
- Some Title Name.avi
! \Cheers (1982)\Season 01\It didn’t and they don’t recommend anyone else do it either -s01e04
.avi
! \Cheers (1982)\Season 01\s01e05
- It was getting dark, and we weren’t there yet - Some Title Name.avi
! \Cheers (1982)\Season 01\Malls are great places to shop; I can find everything I need under one roof -s01e06
- Some Title Name.avi
! \Cheers (1982)\Season 01\Rock music approaches at high velocity -s01e07
- Some Title Name.avi
! \Cheers (1982)\Season 01\The mysterious diary records the voice -s01e08
- Some Title Name.avi
! \Cheers (1982)\Season 01\The old apple revels in its authority -s01e09
- Some Title Name.avi
! \Cheers (1982)\Season 01\The sky is clear; the stars are twinkling -s01e10
- Some Title Name.avi
! \Cheers (1982)\Season 01\We have never been to Asia, nor have we visited Africa -s01e11
- Some Title Name.avi
! \Cheers (1982)\Season 01\We need to rent a room for our party -s01e12
- Title. We need no stinking title.avi
!
I’m absolutely gonna bring on the complaint police on this one, lol…
So, you could append sXXeXX to the end of your filename and Plex should organize them correctly.
01 Doll No. 123.mp4
→ 01 Doll No. 123 (s01e01).mp4
This is not 100% what you wanted but it’s close and you can keep your filename nomenclature, kinda…