If you find that a query including an ampersand only searches for everything before the ampersand, you may need to upgrade your Magento extension to version 3.11.10, where the ampersand is now encoded in the search query.
If you're ready to upgrade, you can follow this guide outlining how to upgrade your Algolia extension and view the release notes here. We always recommend upgrading your dev environment first to make sure there are no unexpected issues.
If you're not quite ready to upgrade, the PR for the fix is here. You can follow this guide to patch if needed by getting the diff of the pull request.