Using USB Tethering with USB-to-Ethernet adapter

I live in an area without any high-speed internet access. Currently, I am using a cell phone hotspot connected through a wireless-to-wired bridge to my home wired/wireless networks. I would like to increase my bandwidth using multiple cell services/hotspots and have not found the complete answer. I have a TP-Link ER605 and am able to hook a cellphone directly to the USB WAN port on that device and it works to provide Internet service. I am attempting to connect a second cellphone to an RJ45 WAN port on the ER605 using a USB-to-Ethernet adapter, but have not found any combination that allows the 'USB Tethering' option to be enabled. I have the following phones: - TCL 30 XL (Android 12) - Moto X4 (Android 9) Both of these devices work to provide Internet service when directly connected to the ER605 with a standard USB cable. I have tried two USB to Ethernet Adapters: - uni USB C to Ethernet adapter (Amazon link ) - Smays USB C OTG Ethernet adapter (Amazon link ) Neither of these adapters enables the USB Tethering option, either plugged into an ER605 port or to a port on a Windows machine. What are the cellphone/adapter requirements needed to support this configuration?