Android USB Tethering to Ethernet to Router

Is it possible to share my phone's internet but instead of creating a Hotspot, share it directly to a router through ethernet

Here's my idea: Mobile Phone (LTE) -> USB OTG -> USB Ethernet port -> Cat5e cable -> Router

Btw, my router isn't supported by DD-WRT so that's off the suggestion list.

Forget the USB as the intermediate. You can accomplish what you want with a wireless bridge adapter that has a CAT5 LAN port.

Program the wireless bridge to your phone's hotspot and then plug the LAN port on the bridge adapter to your Router's WAN port.

This GL.iNet GL-MT300N Mini Travel Router is probably a good bet, as you can program it with DD-WRT for ultimate flexibility. I think someone in the Q&A section confirmed they are doing what you want with this VONETS VAP11G-300. Pretty sure any wi-fi repeater that has a LAN out port for connecting wired devices should work for you.

Newer Android devices with Android 11 come with Ethernet Tethering support built-in. For example, in this setup, I connected my phone (Galaxy S21) and my laptop over a LAN cable:

The Android phone acts as a router itself, which allows internet to be shared without an intermediary router. However, I think you can also use it with an existing router using NAT or bridged mode.