WAN would be the Internet uplink port. A 2.5G WAN port is a 2.5 gigabit Ethernet port. 2.5 gigabit and o a lesser extent 5 gigabit Ethernet are a standard that’s becoming rapidly available on a lot of hardware. OP is stating that for a device shipping near the end of 2024, a new router that is shipping with only 1 GbE instead of 2.5 GbE is a problem.

Not really. WAN has always been WAN. Wireless has always been WLAN.