v2.1.0.119_canary_2025-05-29 release note has this:
To remedy existing data, the test method can now be run and only check index files (
--full-remote-verification=indexesonly).
By default, any defective index files that are found will be replaced with correct versions, so simply running the test command with a large sample size will fix the backup.
UI Commandline can show that like below. Sample size (e.g. all) is Commandline Argument.

EDIT 1:
so I don’t think any special settings are needed, but if you want a faster run, IndexesOnly avoids downloading the large dblock files. If you want a sooner more certain test, the manual run works.