Probably not the issue, but when you check the PC Server, do you find it awake or asleep?
Renderers, including good standalone DLNA targets, should keep the server awake. This was fixed several versions back, but to be sure, you can easily watch Servers & Plug-ins > Reporter > Power on the server while it is playing, as seen in the attachment. The two Power status lines shown appear automatically once play starts. For some devices, you may see these messages expire and renew as tracks change. I don't believe there are any special Options settings required beyond the usual stuff for DLNA renderers.
Server: Win11 Pro 64-bit