I’m not quite sure I understand what you’re aiming for…
Do you want the episodes to still match based on their file names but then manually re-arrange their order?
e.g. your file is named Show Name - s01e01; it’ll download the metadata for s01e01; then you tell Plex to place this in the 2nd episode position instead??
This seems to be what’s already discussed in an existing feature suggestion.
If that’s what you’re suggesting too, please comment/vote in that thread in order to avoid distracting votes (and letting us close this one).
There’s another somewhat related suggestion, discussing an option to manually match episodes.