If you delete collection fields and recreate them the names get generated that way.
You could create a completely new collection but that would also create new collection IDs also.
creating a new collection is not feasible at this point and deleting old names, then recreating them does not seem to get them back to the non suffix version.
it seems the only way forward is to create a new unique name for all the items, but then you have to update your backend, so not ideal either.