My LAN IP is still changing after every reboot, from 192.168.0.1 to something else. I have my WAN DNS set to a local address within the LAN IP subnet, and I lose my internet connection on every reboot

I am transferring files between two computers and both show they are connected at 100 Mbps. One device is hardwired to one Deco and the other to a second Deco. The maaximum speed I get is 10 Mbps. Is