Signal light being blue signifies it is connected to a 3G network (UMTS). Cyan signifies LTE. From your video I can see it's 4G LTE, however.
From what I could see in the video, the stats were:
RSRQ: -12 dB
RSRP: -114 dBm
RSSI: -83 dBm
SNR: 1 dB
The connection is poor overall. I would suggest attempting to relocate the device near to a window, at least for now for the sake of testing - if cable length permits for both LAN and router power supply. You may need to put a bit of effort into finding a good spot which may not even be in the same room, and sometimes just a few centimeters can make a difference - but don't let this you discourage you! Having the device inside the house, far away from windows will stifle a good connection since walls are a good obstacle.
I would really suggest downloading and using LTEWatch
since this can feed you live stats regarding connection signal connection an quality - this may help you find a good spot. It will also let you manually set the LTE frequency band, which is not possible through the UI on the B311 if I recall correctly. Please note: sometimes the application stops updating, or at least I think it did on the B311 - a simple close and reopen of the program will suffice.
If you still have slow speeds and issues after relocating to an area with better signal strength and quality, then it may be because:
- You are connected to Band 20 (800 MHz, which is used for VoLTE on Three);
- Your area is subject to congestion.
In LTEWatch, you can force the frequency band to Band 3 (1800 MHz) - it may be worth giving this a try once you've moved it.
Something important to note with the Poynting 4G-XPOL-A0001 is that the cable is pretty long (5m), and so any gains made will be lost through cable loss. If you are buying this antenna, you really have to be prepared to mount it externally otherwise it probably won't give an improvement because of the loss. In reality, if you don't want to go external, you'd probably be better off buying HAUNT-BL315 (or HUANT-W315, if you want white) antennas. Though, the B525 you've ordered has decent internal antennas anyway.