How to make DHCP server in Android?

I want to move the DHCP server from my OpenWRT router to the admin’s phone (with a static IP) because I need the network to handle 200 devices connecting and disconnecting quickly—about 30 seconds per device, with up to 200 devices in 5 minutes. The router gets very slow after 70 devices, so I developed a DHCP server app for Android. But I found out that it can’t listen on port 67 without root, and rooting all admin phones isn’t practical. I considered using an external device, but I’m worried about efficiency and debugging compared to using my own app. Is there a solution to run a DHCP server on Android without root, or another easy way to offload DHCP from the router while keeping flexibility and speed? The router specs are in the attached image. Image resized. Click to see the full size