Struggling with my set up - Purple; User Jbg232, where are you?

I'm having issues getting a strong enough wifi signal where my kids game. Current set up is Modem/Router (non-broadcasting) -> into Firewalla Purple WAN port (also non-broadcasting) -> from LAN of Firewalla Purple to NetGear Power Line plugged into the wall that allegedly talks to the other Powerline unit plugged in near my kids and broadcasts the wifi they connect to. This isn't good enough. 

My networking skills are weak. I am fatigued from all the variables I have read online. I have looked at Firewalla's suggestions. I have been hesitant to get a switch, can't figure out if I should get APs or Mesh, etc etc etc. But I am ready. 

I want to set the kids up so they quit bugging me or running wire out to the Modem/Router (where I don't get parental control through my Firewalla Purple).

I'm thinking of Modem-> Eero Pro6 in Bridge Mode?? -> Firewalla Purple -> Switch -> other Eeros ???.  If I use the Eero Pro between the Modem/Router and the Purple, I need help with which ports to use, etc. And other people saying they use Eeros plugged into the switch confuse me. I thought only one Eero pro would be hard wired (the one between the modem and the prurple) and the rest would be getting a signal from that one. 

One of the "show us your rack" postings is doing something similar but with a much more extensive set up. User Jbg232 and the posting: https://help.firewalla.com/hc/en-us/community/posts/18333572629267/comments/18364856154643

Someone please help! Would love a reply from user Jbg232.

Thank you!