AFAIK, Wimax is an old technology, Intel no longer develop it while LTE is different.
webe LTE is using Band 5 (most area) which technically able to cover wider area as compared to other telco 1800, 2300 or 2600.
However, TM being a newbie on LTE game, what they lack of are the tower/network/repeater, thats why some area which has more subscribers will encounter slowness.
And that also depends whether your phone can support Band 5 or not.

I've just tested the connection side by side between webe broadband 30gb and unifi mobile.. （both 4G on Huawei E5377s-32)

Random sites loading from google news feels that Unifi mobile respond faster compared to webe broadband..
Also, several test on fast.com indicating that Unifi mobile is at the speed of 1.2mb, 2.4mb and 5mb speed.
btw, I'm in Penang, Bayan Baru area.

I have the Huawei E5377s-32. Earlier, I was finding ways to power up the mifi without putting in the battery.
After a round of research, I think Huawei purposely disable this way of using the mifi, in order for their other bigger CPE LTE modem router can sell. (coz last time TP-Link 3G mifi can power up without battery)

If you're handy with electronics, voltage or have friends who are into mobile repair. Maybe you can directly send the power (power adapter or voltage regulator) to the power pin located at the back of the mifi.