Fun fact: Switzerland operates the only significant G.fast deployment in the world. The technology was such a flop that Huawei stopped making the hardware.
By the way most of the fibre needed to connect the FTTC/VDSL/GFast cabinets was already in the ground and they just needed to splice into it, as it was there for exchange to exchange backhaul, and leased lines. It's the final ~500 metres that's the expensive part of installing FTTP, as that has to be new and there is probably not a lead in duct that is clear so means climbing poles, clearing duct, or new trenching.
Nope. In Germany, M-net (Munich) and NetCologne operate massive g.fast networks, and if you don't want Huawei, go for Adtran's 516 lineup on the ISP side and AVM on the CPE side.
I didn't know about network equipment from other manufacturers, not sure why we're stuck with Huawei here, but it's a dead end. The plan is to migrate as many G.fast subscribers as possible to FTTH in the next 5 years, and eventually to mmWave 5G in a few corner cases.