help with separating reolink NVR system from my network through subnet.

Hello ,

I have been trying to separate my nvr from my network by placing on a separate subnet. Here are the issues I run into and here Is my equipment.

Modem Bell HH3000 Router 1 Archer 10 Router 2 archer 10 NVR reolink 8 channel 4k

I initially had my home network on the router connected to port 1 on HH3000 and the nvr on port 2 of HH3000. The HH3000 designated ips on the same subnet for both. And they could see each other even though the archer had made a different subnet for its own ips . So Router assigned 192.168 2.30 nvr 2.31 .. all my devices connected to Router is 192.168.0.xx which is technically on a different subnet then the NVR but I am still able to ping it.
The cameras can be connected to quickly and no lag but my concern is potential hacking and having the network separated.

NOW my second setup is plugging in an additional Router to port 2 on the HH3000 and it is now assigned 192.168.2.31 So two Routers different ports , but same subnet from the HH3000. However I am now able to assign the nvr to a subnet of 168.4.xxx and my home devices on the other Router are still on 168.0.xx ..They CANNOT see each other and cannot be pinged. Yeay!....... well not so fast. When I connect to my cameras now via the APP there is a good 8 to 10 second delay and when viewing anyitng higher than low resolution it is constantly buffering/lagging.

So, one way I have fast connection to my cameras remotely and no security and the other way I have slow connection with an added layer of security.

Any thoughts on how I can make my configuration work so that I can active both separate subnets and still have fast remote viewing ?

Thanks