3G modem Dongle suitable for BT HomeHub 5A router modem

:slightly_smiling_face: Hello friends
I have a question. Which 3G or 4G dongle modem is suitable for connecting via USB port to the BT HomeHub 5A Openwrt 19.07.9 router modem that is easy and cheap to install?
How are the installation steps? Please introduce some 3G / 4G dongle models that are available in the market.
:signal_strength: Which of the following models are fully compatible with my modem?
:question: DWR-910M Wireless 4G/LTE Portable Modem [ D-Link ] ?
:question: modem USB 3G Asiacell model E3531 [ Huawei ] ?
:question: Zyxel portable 3G modem model WAH1004 [ Zyxel ] ?
:question: ZTE LTE USB modem model MF79U [ ZTE ] ?

Don't buy anything that is 3G only, as the service providers are about to discontinue 3G service-- if they haven't already in your area. Non-LTE modems will become useless then as the only signals from the towers will be LTE.

The cheapest option is to find an old smartphone and USB cord for it and use the USB tethering feature.

The D-Link and ZTE are probably nearly identical inside and would use the rndis driver like a smartphone.

Keep in mind that the bthub5 is not exactly a powerhouse, a hardware upgrade might be wanted as well.

hotplugging USB devices also tends to reboot the bthub, due to bad design.