It never hurts to copy the entire error report (unless very long), remove info unique to your site or installation, and Google it. Using the main parts of your question, ‘woocommerce checkout unexpected token is not valid json’, I got a number of similar reports, though no single fix.
One thing that solved the issue for some users was to re-save permalinks: Go to Admin/Settings/Permalinks, and re-save them – https://www.wpbeginner.com/beginners-guide/how-to-regenerate-your-permalinks-in-wordpress/#:~:text=To%20regenerate%20your%20permalinks%2C%20just,has%20now%20regenerated%20your%20permalinks.
If that fixes it, then you’ll probably call that good enough, and not try to find out why it started happening.
If that doesn’t work, and you don’t find an error report that clearly duplicates yours, you might try this post, which is from 2015, but still useful (and educational!). https://mikejolley.com/2015/11/12/debugging-unexpected-token-in-woocommerce-2-4/
You can also try again providing the full error statement.
Good luck!