So I have converted SP2019 from NTLM to Azure AD auth, setup azureCP etc. To do this I extended the webapp from "servername:80" -default to "https://myurl.com" - intranet. The default zone "servername:80" has NTLM setup, and no azure ad. The intranet URL "https:myurl.com" has Azure AD setup with no NTLM. Search is crawling the default zone, and I have in a server name mapping. The issue is that the links in library / list alerts are pointing to the default URL "servername:80" and not the the intranet URL. URL links in workflows are correct.
Have you added the intranet site url in content source?
Here is an article about extend web application with different authentication and configure search for your reference(please pay attention to the later part in this article):