Problem with Graph Export (and import)

My graph (imported from Roam and worked on in Logseq for about a month) has become extremely slow in Windows, frequently freezing. I am attempting to export it and re-import it (into Roam and Logseq) to see if that helps, but this is not working. When I export as either JSON or Roam JSON, and then attempt to re-import the Graph (in both Roam and Logseq), I get “please chose a JSON file,” and when I attempt to export as OPML the system just freezes. Thanks for any help!