I'm able to connect to all of those servers. One of them doesn't have any public username/password, but I can connect fine to that too. None of them allows me to setup key file authentication.
I'm quite sure it's not a firewall issue as I never did any special configuration for FileZilla or WinSCP. I am also able to connect via WSL1.
Also, I've been connecting to my office server from home via internet and not on LAN/VPN.