Unable to reset Netgear Nighthawk r700 after expressVPN firmware install

Hello

I downloaded and flashed the ExpressVPN firmware from https://download.expressvpn.xyz/clients/router/expressvpn-netgear-r7000-v1.2.3.chk. I'm now trying to remove it and get back to the latest stock firmware. Following the expressvpn instructions at https://www.expressvpn.com/support/troubleshooting/asus-netgear-reset-original-firmware/ does not work as expected after the router rebooted it still has the ExpressVPN firmware. I tried again, tried a different version of the NetGear firmware and finally tried a hard reset (pushed with pin button at back of router) but I somehow cannot get the original firmware back on it. I can now only get to 192.168.21.1 which brings up the ExpressVPN admin UI, can't get to 192.168.1.1. I also tried https://github.com/insanid/NetgearTelnetEnable, but get a connection refused with Telnet. 

ExpressVPN support have been unhelpful so far.

Thanks for any advice on what else I can do.