18/6 now, can I do different?

That's fine. Whatever works best for your heat management with the environment you are in. You have autos so the light changes won't be that be an issue. Happy growing.

I believe you can decrease the lighting time with no ill effect, it will decrease the amount of light the plant can take in and may result in less growth. You maybe able to increase the exhaust fan if you are indoors, add a oscillating fan, or have lights off during the hottest part of the day to help decrease the temps. Portable AC unit is also an option. I am in an attic where temps and humidity vary. Lots of rain this past week so fighting humidity at the moment and sure the temps will be an issue as Summer progresses. Best of luck to you!

Now I’m doing 07:00-13:00 light on.. then 13:00-17:30 light off.. then 17:30-22:00 on, then 22:00-23:00 off, then 23:00-07:00 on

Well, with autos you really ain't trapped by any time settings. If you are having trouble with heat build up after a few hours you could try running your light on a 4-2 4 on and 2 off or 5 on and 1 off. Also if you don't want do it like that, which wouldn't cause any issue to growing as you can run a plant (auto) 24/7 if you want. Also as its hotter during the day time. Maybe change your lighting so the light goes off during the hottest part of the day stuff like that will help. Of course an exhaust set up. But anything under 30c will be fine if you have air flow over your canopy as the canopy temp will be a few % lower than the air temperature.

I forget to say that I’m on flowering week #7