What does Renogy say about the flicker? It doesn't seem desirable and might be an indication of some issue.
Flicker suggests an electrical transient condition that can effect electronic equipment causing shut down, reboot etc.
"As for the flicker, presumably the lighting is operating directly from battery 12v and competing with the inverter, which is also drawing from the battery. As the inverter is stepping up it's amp draw, there will be a tiny drop in battery voltage, and the battery BMS may be doing something to adjust to the new & higher amp draw."
