So I was making my sourdough starter for almost three weeks, and it still wasn’t floating in water. I used this recipe: https://www.theclevercarrot.com/2019/03/beginner-sourdough-starter-recipe/ However, when I was searching, I could not find I could not find unbleached all-purpose flour. So I used bleached flour instead. I do not own a proofing box, so I proofed my starter in an oven with the light on. I didn’t notice it rise much, but I continued to feed it. It was showing some bubbles, but not enough to make it in the dough. For almost three weeks, I kept feeding. After then, it did have bubbles, both big and small, but a lot of times it would have a brown-ish liquid before feedings. It smelled like unbaked bread dough. I was becoming impatient, and decided to make the sourdough dough with the unripe starter. Everything was mixing well, and I followed the directions until I got a nice dough consistency. It was 4 hours into the bulk rise, when my dough hadn’t grown a centimeter. I concluded that this was because of my young starter. Will it still be okay? Any tips for finishing the bread? How can I make a future sourdough starter less time consuming? Thank you!
Using a starter with insufficient activity is basically the same thing as forgetting to add yeast to a non-sourdough loaf. If there's very little activity in the starter, then you don't have an established colony of wild yeast so there's nothing there that will make the dough rise. At this point, your bread is pretty much a loss. You could try to turn it into some form of flatbread by frying small rounds of it in a pan if you don't want to throw it out, but you're not getting a loaf of bread out of it.
As for your starter, the brown liquid is most likely hooch. It typically indicates that you're not feeding your starter often enough. Typically, your starter should be ready for use in 7-10 days from starting it. However, lots of factors like the temperature in your kitchen and precisely what kind of flour you use can affect the time it takes for a yeast colony to establish itself. Using it before you have a stable colony of wild yeast is a waste of time and ingredients since without the yeast it cannot replace commercial yeast in your bread. Patience will get you there faster than rushing.
Some people think cultures tend to develop from microorganisms pre-existing in the flour rather than from the local environment. The idea was put forward by proponents of other types of wild fermentation (e.g. lacto-pickles) and is backed by experiments with sterilized flour. I first learned of this on pizzamaking.com.
It sounds like your culture has aquired some microorganisms but perhaps no yeast. I would think it will be easier to start again with an organic flour, even if it's not all-purpose. I'm not too sure there's a problem with the enzymes being different, as per the linked recipe. The main thing though, is to start the culture with a non-sterilized flour. Once you have an active culture you can introduce bleached flour. It might slow it down but it should still rise.
Another option is to buy a culture online. I've bought and made many over the years but the only one I kept is a 300 year old Italian one I bought from sourdo.com.