Is there any free WiFi network available at the HZMB (Hong Kong–Zhuhai–Macau Bridge) Macau Port?
Yes, there is. According to a free WiFi service site created by Macau government, there are 3 locations/areas with WiFi provided. This site (there's an app too) also provide the locations of all free WiFi hotspots that can be used across Macau.
Somehow the first two result only have Chinese description so let me translate for you.
- Hong Kong-Zhuhai-Macao Bridge Frontier Post at Macao Port - pick-up and drop-off area in car park within Macau's border
- Hong Kong-Zhuhai-Macao Bridge Frontier Post at Macao Port - car park pick-up and drop-off area in car park outside Macau's border