Coordinator -> Router communication slow when some routers are offline

Previously we had a network of (1) Coordinator and (20) Routers that was working more-less flawlessly.
As soon as we added more routers (60) we have some performance issues while sending very little data (just a message with number with 8 digits.)
Additionally as soon as we start to turn off some of the routers, the speeds are getting very low and it can take up to 5 minutes to deliver such simple message.
I have tried lot of settings, so I would like to ask help before I mess it up even more.
Thank you for your support.

This would be considered a Large network. When using large networks, you should be either sending data in broadcast packets or use Source routing via the API interface. The reason for that is that you would have to perform a rout discovery as you are exceeding the routing table size.

Thank you Eric for your answer.
How can we enforce source routing when using XBee Gateway Wi-Fi and we are sending messages that looks like this:


How can we issue ND command?

I have tried to follow this document, but I am bit lost:

The border router firmware is built using the RIOT gnrc_border_router … This module supports communication protocols like HTTP/MQTT/LWM2M/COAP, etc.
buy tiktok likes singapore