I write that i tried to use WS-M181 and HGLRC M80. Both support UBLOX.
Thank you for trying to help. JSV

I am running the stock ATBetaflight 4.3.2 that came on the board, I am afraid I don't have any experience with iNav and suspect the iNav target for that board might be the issue?

I have a Walksnail GPS in my box of parts and put that on to UART 2. All I did was set GPS on the ports tab and set baud rate to 115200. The GPS module was properly detected using both NMEA and UBLOX protocols. Not sure how it will perform outdoors, but indoors on a cloudly day, the Flywoo GM10 Mini V3 was able to lock 3 satellites relatively quickly and show GPS coordinates, however the Walksnail failed to get any 3D fix. Maybe the slightly larger antenna of the GM10 Mini helps it.

Also the NeutronRC board does power up the 5v pads on USB only, so your GPS module should be receiving power without a lipo, but it may be worth double-checking if the module has a LED or using a multimeter.

Thank you for your suggestions. I am aware of the lack of USB power supply. That's why I had a LiPol battery connected.
Problem solved. 
I have HW 1V2 and manual from version 1V0. One GND pad changed to SBUS :-(