Possible solutions coming to my mind (always keep a backup of the original file before trying any of these).
1. Start your wiki in safe mode : in the the browser url, after the .html, add #:safe then reload. This will disable all plugin, then you can go to
$:/AdvancedSearch, in the tab "Filter" use the filter "[!is[system]sort[title]]" and click the export button. You will get a .json file. Next, go to
https://tiddlywiki.com/empty.html, drag and drop your json inside to import your tiddlers and hit save.
2. Drag and drop your tiddlywiki file in the
upgrader, uncheck tiddlymap related tiddlers and see if this fix your issue.
3. Drag and drop your tiddlywiki file into a node.js tiddlywiki. With a bit of luck you will be able to import all of your tiddlers, which will be saved individually. Then you can delete the faulty plugin tiddlers and reimport your tiddlers back to a fresh tiddlywiki.
4. Use the javascript console :right click anywhere on the page, select "inspect". This will open the browser dev tools. Go to the console tab and paste this command :
$tw.wiki.getTiddlersAsJson("[!is[system]sort[title]]")
Hit enter, you will see a json file printed in the console. Right click the output, select "copy object". Then, create a text file, paste inside. Rename the file to .json, and drag and drop your json file to a fresh tiddlywiki.
If nothing works, you can always try to open your tiddlywiki file with a code editor (visual studio code is free and great), search for "
tiddlywiki-tiddler-store" and copy all the content inside the script tags. Then paste it into a new file, change the extension to json, etc.