Android Hotspot Clients Have Their Own Proxy Settings
Android tethering shares a network connection. It does not make a connected laptop inherit the phone’s application proxy settings.
A proxy can work in an Android phone's browser while a tethered laptop uses the ordinary mobile-network exit. The laptop receives connectivity from the hotspot, but it does not inherit the phone browser's proxy configuration.
Android's tethering module forwards traffic for attached devices. A proxy-aware browser instead opens a connection to a proxy service. Sharing the phone's network connection does not perform that application-level step for the laptop.
If the laptop can reach the approved remote proxy, configure its browser or application with that endpoint. To use a proxy server running on the phone, the server must accept clients from the tethered network and provide an address reachable from the laptop.
On the laptop, 127.0.0.1 still points to the laptop. It cannot identify the phone's listener.
A VPN-style forwarding app may provide another traffic-sharing arrangement, depending on the app, Android build, and tethering support. Check the laptop application's actual exit separately; a phone-wide routing claim does not establish coverage for attached devices.