I thought the same.

I suppose they use stuff like real-time-kernels.

Depending on your needs, a typical wifi router would need

• some ARM SOC (optional) with a CPU with at least 1 GHz speed
• 500MB RAM or so
• 4GB of storage or so
• PCIe (or m.2 or miniPCIe) slots to plug in
  • 1 WAN ethernet port, 1Gb/s up to 10 Gb/s
  • optionally a modem for fiber or whatever you use
  • 1 or more LAN ethernet ports, a bit lower speed
  • a wifi card (no idea why the Omnia has 2) with support for Wifi6
  • a few antennas, 1 or 2 are enough, to plug into the wifi card
• power supply
• USB or some other form to flash updates locally

The software needs to run on there, being Linux based that should be absolutely no problem. But a RPi5 afaik still has no upstream Linux support, but it also way overpowered for that job.

I totally think about building my own router, but also enjoy the service of Turris, their advanced OS that requires these high specs, their package repo and custom OS features not present in upstream OpenWRT.