Per
@go go kid, I suspect that pot size can impact on plant size but I have large plants grown in 5 gallon buckets.
Autos aren't some weird beast. In the same way that breeders cross breed cannabis sativa and cannabis indica to get the traits that they want from those strains, breeders breed in genes from cannabis ruderalis so that the plants will go into flower after a certain number of days. I only started growing in 2021 so I don't have any knowledge of "the bad old days" of autos but I have zero interest in folks who can't move past that. Sure, they sucked. That was then, this is now.
My first 5 or so grows were autos and, since I didn't know that they sucked, I just treated it like a cannabis plant and biggest problem I had was keeping them in the tent.
Regardless of the environment in which your growing autoflower cannabis, it's a cannabis plant. The attached graphic shows the parameters of the grow environment. Step through each one, learn about how it applies in growing cannabis, and then apply that knowledge.
Growing cannabis isn't rocket surgery - follow the basics and it will turn out pretty well.
Friggin autoflower can't stay in the tent (that's one plant).
And my beautiful photoperiod that got bud rot (Spring 2023)