Combining local WiFi into ethernet

I haven't quite found exactly the same question on the forum so here I ask. On my garden I have small 5G router that provides WiFi for remote controllers (water timers, lights etc). I have inverter from Epever that can be accessed through provided WiFi adapter so if I am connected to the Epever WiFi I can access all the settings and monitoring. Now there problem is this WiFi adapter works only locally, so I can only access it when I am connected to it's WiFi. Is there any possibility to merge this local WiFi into the 5G Router so I can connect and monitor the settings through the Solar Guardia

Question by Frosty 2k on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.