R7000 as VPN Server behind an R7800

Just bought a new R7800 and wanted to use old R7000 as a VPN server to access devices on my LAN at home while at work.

R7800 local LAN ip 192.168.0.xxx

I set R7000 local LAN ip to 192.168.1.xxx with WAN ip static to 192.168.0.3

Connected WAN of R7000 to port on R7800, DMZ'D 192.168.0.3 on R7800.

Have not gotten as far as testing from remote for VPN access as I am am concerned that I am unable to access R7000 remote administration page from work.

Remote Admin port set to 8443.....Using dyndns for ip on R7800....sort of works.....when browsing to admin page on R7000 with proper port it quickly returns unable to connect, but if I just use a random port entry in browser it hangs for awhile before timeout so I know R7000 is getting request but refusing connection.

Both R7800 and R7000 are running up to date stock firmware. If I have to I can reflash to different firmware on R7000, but only looking for server capabilities so figured stock is fine.

What am I missing here? Googled the crap out of this scenario and all I find is people wanting to use second router as a client.

Thanks in advance.