I have the same problem when using a quest3. I think there's something wrong with the way skybox connect to the smb share...because if I connect to the skybox installed on my windows machine, then, everything works. if I connect to the same windows 10 using smb, then it's extremely slow...so it's nothing to do with my wifi router or anything. the wifi connection is fine.
and, btw, this issue only happens when I connect to my windows 10 machine. I have a NAS, and smb share works there, nas doesn't have any problem.
my understanding is that...skybox has implemented its own smb client, right? using what? smb1? smb2, smb3? maybe there's a upgraded lib that you guys can use?