50 GB is a pretty large file to transfer over WIFI. Have you done a lan speed test? WIFI speeds can be affected by many factors: distance, construction materials used in the house, other WIFI networks in the area, etc. Is this just a one-time file transfer you are needing to do? If so, I would try using a wired ethernet connection.
I occasionally backup some files from one computer to another on my wired network and a 100GB file takes less than 30 minutes.