I'm not surprised by the corporate network, it's pretty common for those types of networks to severely block inter-device LAN communication. There are two solutions however, for one, KDEconnect has initial Bluetooth support. I think it only support Plasma and Android as of now, and could be documented better, but it does avoid the LAN access problems. The other solution is using a VPN, the easiest off the shelf solution being Tailscale, but I feel this is only worth it if you have multiple use cases for it (I use it for faster Syncthing transfers, Moonlight / Sunshine game streaming. And KDEconnect)
I really wish KDEConnect "just worked", similar to how Apple's devices connect to one another, but I guess this is the price you pay sometimes for an open source cross platform solution.