Slow Wi-Fi speed on MacBook with ZTE F680 router. What settings to set?

Question

WiFi

The router has changed from Keenetic Extra II to a router from MGTS ZTE F680.
On the phone (OnePlus 5T), the speed is around 200. And on the MacBook Air, the speed is as unstable as possible, most often it shows from 4 to 60. I tried to dig deeper in the router - nothing has changed. How can I configure the router or what can be done at all?