My info may be outdated as I last had G Fiber about a year ago but have moved out of their service area :(

When I first got the 2G down/1G up G Fiber service there was no bridge mode & had to use their provided device as modem+router+wifi. They updated it to add in a bridge mode option but I never tested it. I had dropped back down to 1G down & up before that options was available.