@Debgram If there's no other way to power the security camera (like power adapter plug) except PoE you'd need a PoE injector.

@Bababui Go through this thread to check if that's the problem with the slow speed.

@newtodeco Only Deco uses the app for management/configuration. All TP-Link routers have web management interface and can be managed/configured via Tether app as well.

@newtodeco To manage/configure Deco you'll need the Deco app. There's a limited features available through the Deco web interface - details. Here you can download the Deco XE5300 user guide.

@Bababui If all Decos are connected to the switch they should be set in AP mode. When set in AP mode you may consider disabling your main modem/router wireless radio to avoid wireles interference....

@cooler-master The topology seems fine. If you have any dead spot on your first floor you can set 2A: Optimum Gateway (bridge mode) --> 2C: Archer 1500 router #1, wired (if that's possible).