Less work is always better, IMO. At the moment, I've been running with filter floss in my overflows that I replace weekly with the water change. I have bioballs in the AIO but even thinking about reducing them.
I think your issues may relate more to new tank immaturity (i.e., environment still growing) so patience is probably your best friend at the moment. My tanks always run better after the 9 month mark.
I'm still thinking about the whole CO2 instability thing. I'm not sure that matters much as long as plants are getting what they need which is likely a range of CO2.