I’ve tested this a few ways, and the speeds on GL-iNet firmware are still slower than ROOter Goldenorb.

3.029: 15Mbps
3.105: 15Mbps
3.029: 15Mbps
3.105: 15Mbps
ROOTer: 20Mbps

These speeds were tested using stick antennas instead of my external antenna, using the same speedtest settings and the same LTE band. I did about 5 tests on each firmware to try to make sure that the speeds were similar.

On ROOTer, the signal is consistently faster than either of the GL-iNet firmware.