Looking for a telco solution for office fibre/wifi and mobile, so everything under 1 billing.
Around 5-10 mobile numbers.
Office internet is to serve from 5 to 100 people.
We will do alot of Online meetings, Video upload and Streaming as well.

I can only think of Maxis, any other option?

maxis, digi, TM, celcom, YES also got.

in west m'sia, most of it is lease fiber backbone from TM.
except small percentage of places got maxis own backbone, & some YTL project has their own fiber backbone.

in you case, better stick wit maxis or digi.
unifi mobile imo, still a lower tier telco.

noted so that means the maxis/digi internet for office will most likely be using TM (unifi) backbone?

correct.