Thanks to your reply.
Yesterday, I received Rogers Ignite Technicolour CGM4331COM gateway router. This new model router has few drawbacks - cannot disable DHCP and cannot use windows dns server. As a result the entire home lab is broken. I will have to rebuild the lab after, I get another router with WAN and LAN ports so, I can enable bridge mode on the new Rogers Ignite modem and route the traffic through my router.
Not sure what will happen to Let's Encrypt SSL certificate that was issued to Exchange Server 2019. As of now Exchange Server 2019 is DOWN due to change in Private and Public IP Address within the lab.