Pfsense routing between OPT subnet and LAN subnet

Hereafter is my today address plan and related cabling which works partially.
on top of this picture I have in mind to offer a OpenVPN connection NATed to the OPT subnet (but this is for later because the first step does not work).

internet---GW---192.168.4.0---PFsense/lan---192.168.5.0---router---192.169.1.0
                             |
                             -PFsense/opt---192.168.6.0

the picture is more delailed:

the traffic between internet & 192.168.1.1 subnet works perfectly

the traffic between 192.168.6.0 subnet and 192.168.1.1 subnet does not work

I have looked at many answers in the forum and tested a lot of the proposed solutions and I was stuck until … I rebooted my pfsense appliance.

Thank you @Colt for your sharpness and your suggestions

@Tommiie I thank you for the very valuable debugging guidance

In case you are interested in the firewall rules and the router settings, feel free to ask me, I spent so many hours on this ans I am happy to share the screenshots of the settings.

Following the good suggestion of @Colt (see the comments) I don't remove the faulty picture, by "faulty" I mean the set-up that does work !

I rather add a picture with the working set-up one.

In all cases, be sure to reset the FW states before testing a new FW configuration.

hoping it helps !