@Vydrakk noted that they viewed the Personal Dashboard without issue, then changed some preferences, after which they began seeing an error, instead of edits, in the Review Changes module.
They tested in Chrome and Firefox, tried disabling all Chrome extensions, and tried with ?safemode=1.
In Chrome:
Error: Cannot read properties of undefined (reading 'query')
In Firefox:
Error: can't access property "query", rcData is undefined
The preference they changed was setting the 'Prediction threshold' preference to 'Very likely have problems', which has to go much further back in Recent Changes to find enough edits to return. This sometimes caused timeouts, which results in this error.
It's not intuitive that this preference would impact interfaces other than Special:RecentChanges. Ideally we should be able to fetch high revert risk recent changes without ever considering what preferences the user has set.