OK so , finally my processing 30mbps upgrade package done , waited 3-4 working days . RM179 with free call + aneka hypptv .
Tested LAN , always stable 29-36mbps .
IDM max download speed up to 5.09 mb/sec on WiFi .
Play store getting 4.x mb/sec on WiFi .
YouTube 4k streaming smooth on WiFi .
Problem appeared when using WiFi , even next to router get max also 23mbps (always at 20mbps) . *cheapo unifi default router issue*
Kinda solution : go to router *192.168.0.1* , click "wireless settings" , click "manual wireless network setup" , 1) check " enable auto channel scan" , 2) choose "802.11n only" , 3) channel width 20mhz .
After above settings applied , not just next to router but get good coverage at same floor as well 8-10 meter , WiFi stable at 29-36mbps . not getting quite as much coverage at second floor but still quite respectable at 20-26mbps (always fluctuating) .