Yes, this is true.
This is individual, regardless of whether you are on steroids or not.
The principle of progressive overload is essentially common sense, and it seems like they are using it lol. And I think they are right. The interpretation online is wrong. What causes growth is the effort expended when performing a set, not the increase in weight itself. The ability to increase the weight is a gauge of effort expended since the muscle has grown.
Unfortunately, we usually have geniuses who will lift with the same weight for a year on a bodypart split, which would imply a lack of effort, then start something like Stronglifts where they are forced to train with full intensity or they will get crushed by the weight, then the declare they have finally found the Holy Grail of training and bro splits are for roiders because they made no gains when all they needed was some common sense.