Slow Growth for autoflower's

So I’ve been growing a set of autos for almost two months now and they’re growing really slow

two months will be on the 15th. The biggest plant is a Candy Kush, the other two are both AK. The smallest plant I started on the 14th of April so its coming on a month tomorrow. There’s discoloration on some of the leaves from some thrips i had to deal with these past few days, put some neem oil on the leaves so hopefully that helped it seems to have worked so far. My temperatures have been steady around lower 60’s at night to mid 80’s sometimes during the day right now. My humidity is garbage around 16% usually but i’ve had a humidifier in there for about a week and its been doing alright on somedays getting to like 28-30%. The light im running right now is a Mars Hydro SP150 and a crummy home depot grow light just for added light. I ordered a SP250 so that will be here soon to replace both of those lights. I’m not really sure what might be stunting the growth so any feedback would be helpful thanks!

I struggled with humidity too finally , I put a bucket of water in the tent. Then I soaked a rag and left it 2/3 in water and set it on the lip of the bucket. Humidity 43 percent now. Before I did that mine was about 20.

It is possible that it could be just the plants genetics. That is only 8 weeks as well. From my understanding, this is around where most strains start to go to flower. Once they flower though, they can get up to 50% bigger.
Otherwise there could be some environmental factors needing to be changed?
From my understanding, you can force some to flower by switching to 12/12 because if they aren’t high on the ruderalis genes it’ll affect the “auto flowering”(I’ve read where it might be necessary, and others who have done it to force). Mind you, reading and experience are two very different things and I only have a grasp on growing at this point.