ZyXel USG60W - 0 upload speed & limited WiFi range

Hello,

I have purchased 3 USG60W which I plan to setup at 3 different sites.

I have a 100/100 dedicated fibre connection at each site. I have setup the first ZyXel USG60W and upgraded to the latest available firmware for my region (UK). However I am noting that the WiFi range is much much lower than the bog standard ADSL BT home hub which was in place as a temporary broadband before the Fibre line was installed.

Additionally, the quality of the connection is extremely poor - I initially I only had 1 device connected to the wifi which was about 50 CM away from it and web pages load very poor - upon doing a speed test I get the following:

15 Mpbs download

0.01 Mpbs upload

When I connect the same device to the BT home hub on ADSL connection regardless of how far or close I am to the hub, I get 4 Mpbs down and 2 Mpbs upload.

The device is a windows 10, Asus Laptop. I then tried with a Samsung Galaxy 9 Android Smart phone - same results.

When connected to LAN I get 100/100 Mbps up and down no problem. I expect to get lower speeds on wifi as it is slower than connecting via LAN. But these speeds are diabolical. and the Upload speed is always 0.01 Mbps which is just unworkable as once this site is live (end of this week) most of the users will be using wireless devices to connect and work from.

Please note that I have been using the USG series for the last 10 years. I have setup USG60W for about 8 clients in the last 3 years (My company is an IT providor) and have never had any problems with wifi on these devices.

I have been trying different settings for the last week and seen no improvement. The one thing I did notice about these USG60W's is that they use less amps than previous models - these are 12v 2.5 AMPs and previous models I purchased for clients were 3 AMPs. Does half an amp difference really impact wifi performance that much??

I would appreciate any guidance on that as I am about to give up on ZyXel all together at this rate.

Thanks

Andre