By default the linux smbclient mounts smb shares using smb protocol version 1.0 (now deprecated). resulting in slow transfer speed against Windows 10 shares. by adding vers=3.0 to you mount options you are using smb protocol version 3.0 with greater speed.
mount -t cifs //192.168.60.202/föreningar "/mnt/share/radion/k2/foreningar" --verbose -o username=backup,password=mypassword,vers=3.0
More info in this stackexchange thread about cifs randomly losing connection to windows share