My router has a pretty descent firewall so i feel like it should be safe? Maybe. Obviously I won’t be signing into any online accounts or anything like that on the XP machine. Is this a bad ideas? Obviously using Windows in general is a bad idea but I’m sort of limited by the hardware here.
If you can, I’d just block connections from this WinXP box to the Internet completely, then it should be fine.
I don’t know the reputation of this host, whether it’s a C2 slave/bot or other malware.