It does look like your code has been damaged significantly based on the fatal error you post. I wouldn’t expect this to have anything to do with DDEV-Local, but we’re happy to support you more interactively lots of places, see https://ddev.readthedocs.io/en/stable/#support-and-user-contributed-documentation
The wp tool is bundled in the web container, so you can use ddev exec wp ... any way you want.
So in @arufasari ‘s example, ddev exec wp core verify-checksums – for example:
$ ddev exec wp core verify-checksums
Warning: File should not exist: wp-config-ddev.php
Success: WordPress installation verifies against checksums.
You can also use ddev ssh and then just use the wp tool, so ddev ssh and then wp core verify-checksums
