Mobile Data Connection switches to 3G while making call.
I have used 3 models of Asus viz, Max Pro M1, Max M2 & Max.
All phones have same behavior like - if we use Mobile Data on hotspot,
if we make a call or receive a phone call while hotspot is on, mobile networks switch from 4G to 3G.
It degrades the internet speed for clients or almost of no use when call is going on.
If Asus can keep this option for use to set if user want to switch to 3G during call or willing to stick to 4G,
it will solve thee internet access problem during call is going on.
Other make phones do manage this and it is quite helpful feature.