How to connect to Alexa speaker

Try bluetooth

https://www.centerpointit.com/how-to-connect-an-iphone-to-an-amazon-echo-device-and-play-music-on-alexa/#:~:text=On%20your%20iPhone%2C%20open%20the,device%20is%20in%20pairing%20mode.

You are bound to have issues when you buy products with different architecture from competing companies.. and particularly when Apple is in the mix because they expect their people to remain inside the 4 walls of the Apple garden. Don't play with the neighbours!!

Not sure this has anything to do with airport routers.. !!

See if any of the following articles can help:

• How to Connect Echo and Alexa to Wi-Fi - Lifewire
• How to Fix It When Alexa Won't Connect to Wi-Fi - Lifewire