I suggest you try to buy the Bebas SIM and try what Band is there available.
Test the line for a few days and also the speed.
If you have only Band 5 connected, I suggest you stay with Streamyx because Unifi Air is really slow on Band 5.
If connected to Band 40 and can get full speed of 8 Mbps (Bebas got cap speed of 8 Mbps), you may try to subscribe for 1 month and put it inside the phone.
If got good speed, then proceed.
And I suggest DO NOT take the device bundle because the modem that TM gives got so many issues and complaints.
Better to buy your own modem and the plus points of owning your own modem is you can put any SIM you want besides the TM modem which locked to unifi Air only.
Well I suggest to buy the Unifi Bebas SIM and try what Band is there as I explained above.
Only RM10.
But I cannot confirm whether the new SIM will get free BEBAS for one month like previously.
If don’t have, just buy for 1 week at RM20.
Try kaw-kaw.

Then you can apply via online or show proof that your area is able to get the speeds.
That is what I do when I try to migrate from Streamyx to Unifi Air.