I've recently received a pair of Deco Be65 routers and would like to hook it up to my current Deco X20-DSL modem router.
My ISP is Superloop in Australia using i think VDSL2 & ipv4 set up. 
The X20 DSL is our only modem router not supplied by our ISP, but works nonetheless. 

Our apartment only has one connection point for our X20 in the living room and works fine for all rooms except the main bedroom located at the end of an L shape corridor, which has a terrible connection. We've since added a wifi extender for that room. 
We've both used wifi for PC gaming and I must say my connection has always been great, but the extender network is stable on most days. 

Instead I'm hoping to use the X20 DSL already to create a mesh wifi system, with the Be65 as access points and wanted to do this wirelessly (for convenience) but not opposed to daisy chaining them for a more reliable connection. 

I've set up the two Be65 with the X20 as the Main Deco, all through wireless backhaul for now and connected both Be65 via ethernet to our PC. 
At first the connections in both room were great for about 15 minutes, then continious ping spikes. 
Changed the connection from the Be65 to wifi instead on both PCs & that had the slightest improvement, but still our games where unplayable.  

Q: I'm not sure if there could be a potential issue with Double Nat between the 2xBe65 & X20.
Q: If so could using Ipv6 resolve this (i believe my ISP can provide this) 
Q: If not currently my Deco app advanced settings mentions the network operation mode as DSL Modem Router (default) and no option is set up the Be65 as access points only,
so this happen automatically? 

Q: Should I just daisy chain them all together to avoid the hassle with the wireless backhaul setup? 
I hope we're at a point where I can achieve a great connection via WIfi thru the Be25's like it was when the X20 was the only wifi point. 


Any tips and advice are great appreciated and thank you all in advance.