Hi aarex;
Welcome to the forum.
Thanks for providing such a detailed posts. The only other thing I can think that you should check is the short power cord that connect the generator to the cabinet. If you have a multimeter check the continuity of the hot, neutral, and ground wires. Unplug and plug the short power cord several times, especially on the generator side. If that doesn't work, open the generator and check the wire connections at the plug, and make sure none of snapped off.
I don't have the dial type model, but could you explain when the light flickers, does it do it at all settings, or at the lowest or highest.