Bridging iOS hotspot into existing WiFi network on a boat

Garmin Chartplotters have wifi to connect your tablet or phone to them to use their app in conjunction, however they only work as WiFi AP’s and can’t be a WiFi client. Problem here is if I want my non cellular iPad to connect I won’t have internet on it.

I’d like to somehow bridge (hope that’s the proper terminology) the hotspot from my phone into the WiFi network the Chartplotter creates.

Any suggestions?

Was looking at some of these open WiFi routers, but not sure if they only route as I don’t want to create another network, or if they can (bridge) https://www.gl-inet.com/products/gl-ar150/

Thanks