My use is I need an internal network for laser tag activity with 40 guns. Client device .  All guns are connected to the internal network.
 

 Sometimes it happens that he fails to receive at all. And there are areas where he absorbs everything. I operate 2 and sometimes 3 units deco x60 . What is the best way mainly I use network 2.4. I need a particularly powerful router that will be stable. Should I connect the deco x60 as a range extender or is it strong enough? I need a strong memory and no network interruptions. I mainly need an internal network not an external external user.

Maybe actually connect them to a particularly powerful router?  Why are there areas where I had no reception of the weapons at all? I connect the routers with an external 12V battery

 Each of them has been updated to the latest version