This indicates a networking issue of some sort. Try power cycling the router making sure to wait at least five minutes for the router to finish booting before attempting Internet Recovery Mode again. You can also try a PRAM Reset as well (hold the reset for at least two chimes).
Try connecting the laptop directly to the router using an Ethernet cable and a USB-C to Gigabit Ethernet Adapter for a faster more reliable connection which also bypasses hard to troubleshoot WiFi issues.
If this laptop still boots normally (or into Safe Mode) or you have access to another Mac which can run macOS 10.13 to 11.5, then you can create a bootable macOS USB installer using the instructions in this Apple article:
How to create a bootable installer for macOS - Apple Support