This extension redirects to the product page when the search (and advanced search) page should return only on product, even if this happens after the search or after applying a layered navigation filter.
composer require mse-sv3n/m2-single-search-result
bin/magento setup:upgrade
If you have any issues with this extension, open an issue on GitHub.
Any contribution is highly appreciated. The best way to contribute code is to open a pull request on GitHub.