You have to utilize the Menu Items feature of the portal in this use case. There are two options to take here:
Create a grid view extension and get the Share URL.
Use the URL generated to embed Airtable view.
Note: If you do not want to use controls in the Airtable view, make sure to turn off the toggle on the left side (screenshot above) before copying the URL from the embed code.
Once you get the URL from either of these two, go to Menu Items and put them there. Make sure to select Embed in Portal.