You can exclude a specific URL from being loaded into the PWA. This way, if visitors access that URL from a mobile browser, they will see the classic mobile version of your site instead of the PWA.
1. Go to the Advanced Settings screen of WP-PWA plugin.
2. In the settings box, go to Exclude URLs in the PWA and type or paste the URLs that you want to exclude (one per line).
3. Click Save changes.