I’m awful at diagnosing but here’s what chat says. Please note, ai is kinda retarded at times so take this analysis with a grain of salt! lol

When I look closely at the leaves, I notice white spots on the serrations. This could be due to excessive lighting. This, in turn, can mean that the plant cannot absorb enough nutrients

Yes, friend, that is exactly the phosphorus deficiency… I have the same now in flowering, but that is phosphorus deficiency: dark brown spots with a little twisting…

I’m running a 320w 281b+ quantum bar at 70% in a 70x70cm. Should i get down to 60%?

I have a 240-watt lamp in a 60x60 tent. It’s roughly the same, and when I’m at 180 watts, I notice they’ve reached their limit. If I don’t defoliate properly, condensation forms on the leaves that touch each other. Additionally, I have the impression that they are developing minor deficiency symptoms even though I provide them with enough nutrients. I try to keep the moisture in the substrate between 40 - 60%, which should be the optimal range for plant uptake. Unfortunately, I can only adjust my lamp in 25% increments, so always 60 watts. Otherwise, I would go to 150 watts, which I unfortunately cannot do. Try to see how they behave if you illuminate them with 150 - 180 watts; your tent is a bit larger. If it doesn’t get worse, you’ve found the error. And always pay attention to the serrations of the leaves; if they bend upwards and turn white, they are getting too much light, which means stress for them.

Let me know if you notice a change.