It’ll work if the PC is on the same network as the Wifi Expander. There a lots of ways to configure a combination wired + wireless network so it depends on how you have the Access Point set up. But a quick rule of thumb is if the PC’s IP address starts with the same three digits as the WiFi expander’ IP address then it should work. It also can work if they’re not the same, as long as there’s a path from the PC to the WiFi expander via switches and routers etc. It sounds like you have the switch connected to the LAN port of a Wi-Fi Access point. If the AP is configured as a router then it should be ok
I have a fibre broadband modem / router going to a 24 port network switch, with all the PCs, sub-switches and and Wi-fi access points on the same network hard wired to the 24 port switch, all devices with IP addresses 192.168.0.xxx.
From your description I should be able to see the Wi-Fi Expander from the networked music PC and also the rack mount PC I run virtual instruments on.