We use the standard SharePoint Search page throughout the organization, in a browser when you click on a search result it opens the document in Office Online/Win32 app. However, if I add the exact same Search page URL to a Teams channel tab using the Website option, when I click on the search results instead of opening the document all it does is download it! Where is the option to view the document only, rather than downloading it?
I'm not sure it will work! Teams has issues with displaying SharePoint webparts and interact with them properly! Try adding the SharePoint page as a website tab instead and see if that changes anything!
@adam deltinger - as you can see from my post I have added the search page using the channel Website option using the same URL that works OK in a browser. I have not used the SharePoint option because that doesn't allow you to add a URL, it only allows you to add a page or a list. The Standard SharePoint Search page is not a web part.