I have come across this on a Magento 2.3.7 site, when trying use translations to alter text like "Jot us a note" on the contact us page.
When I used that grep command to find the issues, it came back with just 2 results, both from the dev tools:
Check you error logs. For me it said Observer XY must implement Magento\Framework\Event\ObserverInterface
So I had to change my class from
class XY implements \Magento\Framework\Event\ObserverInterface
A neater solution would be to use:
ALTER IGNORE TABLE catalog_url_rewrite_product_category ADD UNIQUE KEY (url_rewrite_id, category_id, product_id)
This forces MySQL to delete the duplicate entries on the table, after which you can delete the new index if you wish too.
you can try removing this line Magento\Quote\Model\QuoteFactory $quoteFactory from construction and run di compile. As per above the the error message is saying that 4th object it is receiving $quoteFactory instead of MessageFactory.
And delete generated folder, as all these factory classes will be generated and saved under this.