i switch from unifi to maxis.
using tm modem since unifi, just change router provided by maxis.

regarding speed, i cannot comment much as i switch from 500mbps unifi to 800mbps maxis.

hard to say about stability as i just switch to maxis this year.
while im using unifi about 9-10 years.

if im not mistaken, during my usage with unifi, only less than 10 times problem (outside cabling).
tm still take 1-7 days to resolve the problem.
the last problem takes almost 2 weeks, that what drive me to change to maxis.

with maxis, i got 3 router (WIFI6) for wifi mesh.