I've not actually done this myself, but I believe all of those guides expect you to place the bridge on the LAN side of your existing (ISP) router - i.e. the WAN port of the opnsense box would be connected to the LAN port of the existing router, and the LAN port of the opnsense box would be connected to a LAN switch - so like Internet<->Router<->Bridge<->LAN.
How does your router connect to your ISP? If it is PPPoE a transparent bridge in that position does not make sense. If it's DHCP or static, it can work, but you will have to give your OPNsense a separate management interface and connect that to your internal LAN.
The transparent bridge won't have an IP address. It just bridges from your ISP to your router and the latter will continue to get its IP address from your ISP via DHCP just like before. No DHCP server on OPNsense anywhere!Make sure you disable the firewall in OPNsense for initial deployment.When that works, connect the management interface to your internal network and set it to use DHCP for configuration. It will get an IP address, gateway, DNS ... from your router and can be used to manage OPNsense from your PC and to pull updates, sync the time, etc.Then you can investigate how to set up the transparent bridge to actually perform some filtering.HTH, good luck,Patrick
I don't know what you can and cannot do with this transparent bridge setup. I have never used it and probably never will. I always connect OPNsense to the Internet as a router and have strictly internal access points for WiFi. Sorry.
Don't your current device(s) have an AP mode?
with this setup can I setup adgaurd dns to filter all the traffic or do I need to dedicated a port to be able to do it so then devices on my network can get an IP from it?