NR2101 - 5G networks unavailable after firmware self-upgrade in Czech Republic

RaStr

EDIT:

I have found out, that 5G is not strong enough in my area. When I have moved, I was able to connect to 5G network. So the original problems is different - LTE has become about 50% slower after the upgrade, what made me think that I must have been on 5G before since the speed was higher than usual LTE speed. 5G speed was now even lower, but that might be a problem of particular provider (T-Mobile), I will have to test it with O2 and Vodafone too if it is the same or different.

I have purchased brand new NR2101 which I intended to use for 5G connection. It was able to connect to 5G network and it has found a firmware update. Since the speed was not as high as it could be I have decided to apply Network Firmware update with autodetected newer firmware expecting maybe improved performance. Since the upgrade the router is not seeing any 5G network in my country (Czech Republic). I have found out that there is alternative firmware for NR7101 with support for 5G NSA; B8 & N1 here: https://support.zyxel.eu/hc/en-us/articles/360021563900-NR7101-Connectivity-issues-and-firmware-fix-for-unsupported-frequency-bands-5G-NSA-B8-N1- which might solve the same problem on my router too I believe, but there is not version for NR2101 available there. Can you provide me with or the old factory software or new software with the proper 5G support, please? I have invested in this modem specifically because of 5G and without it, it is useless to me ! Current firmware in the modem is V1.00(ABUS.3)C0 .Thank you.