@Katt No matter the reason you chose those crazy colors, I think they're really pretty and would look stunning in a picture book! As long as you keep the same color palette, even if you mix them differently each time, I think it would still look consistent. It's a style that stands out! That is SO difficult to do, to find a look that's pretty and marketable, but unique too. You have something special here, don't abandon it by trying to make all clean digital art like everyone else
I would encourage you to experiment more with that style again, and figure out process and method that you feel comfortable and happy with. It's also easier to keep working to stabilize a style you've used in the past, than start from scratch trying to find something else brand new.
I think this may be partly your problem here. You have things that you liked and gravitated towards in the past, for many reasons (feeling free, working around difficulties with colors, enjoying watercolors) but instead of leaning into those things that spoke to you, you're going away from them and starting from scratch. It's like you're re-learning all over again, which may be why you feel like some of your newer work is actually worse.
Experimenting is an important part of the creative process, but it's meant to help make decisions and lean into something, eliminate others. You try something new and then decide: Did I like this? Do I want to do more of this, or is this a hell no? It's a process of elimination. You shouldn't start from scratch every time. You should look back at what's worked for you in the past, what you enjoyed most, what displayed your strengths the best and hid your weaknesses the most. And then you lean into THAT. That's your style