Ever since 19.xx version, using customized map (such as OpenStreetMap) in China will get a massive GPS error of ~1KM. The latest Fenix has fixed this issue in the 18.xx firmware, but unfortunately Garmin did NOTHING for 965 in the 20.26 firmware.
Please treat this as a serious problem and fix this bug (which was initially reported in June 2024 !!!) as soon as possible, or customers will move away from Garmin in their future product choices. OSM and TOPO map are EXTREMELY important for outdoor activities.