Hi,
The Epson XP-7100 is listed in About AirPrint - Apple Support as a model with support for the driverless AirPrint technology. An AirPrint-enabled model is compatible with macOS and can be used without the need for additional drivers, provided that the printer and the Mac computer are connected to the same network (Wi-Fi router).
Are you using AirPrint (that is, without printer drivers from the manufacturer)?
How is your printer connected (Wi-Fi or Ethernet)? AirPrint works with wireless (Wi-Fi) or wired (Ethernet) network connections, so you have a choice with this model. A printer connnection by Ethernet to one of the LAN ports of a Wi-Fi router may be more stable (computers/devices can still print wirelessly, via the router).
If you are using AirPrint, and there is a discovery problem, you could try the following full procedure (in this order, and with these waiting times):
Power off the Wi-Fi router, the printer, the Mac mini, and all other devices/computers. Wait two to three minutes. Power on the router. Wait two to three minutes. Power on the printer. Wait a minute or two. Power on the Mac mini. Finally, power on all other devices/computers.
Add a printer to your printer list so you can use it on Mac – Apple Support (UK)