Yeah, youtube guys tend to expect you to have a higher level of understanding than new users commonly do. It can be frustrating, but they are trying to help the most people. The learning curve for everything is steep as hell to start, but lowers over time.
The small test pieces look good overall. Perhaps a little more retraction distance, less speed. I don't have a bowden, so I'm just guessing based on reading.
Bed adhesion is 99% of the time a leveling issue. Clean with alcohol to make sure there's no oils on the bed, that's safe for most bed types. The ender shouldn't need stuff like hairspray. That's more for plain glass. Your bed has a coating of stuff that is supposed to help with adhesion. For example, my lulzbot has a PEI bed. That needs nothing at all for ABS and PLA, but nylon and PETG can fuse to it, so we use glue sticks to create a release layer. Heat helps with adhesion as well, but too much can make the part prone to getting squished under the weight of the plastic above it. For PLA, I find a 60C bed is plenty to keep it stuck nicely.
You shouldn't need rafts for anything flat on the bottom with good bed contact. I almost never use rafts, they are a pain to remove later sometimes.
Use the paper or feeler gauge to level the bed in at least 6 spots over the whole bed throw. You want to make sure it's the same in every nozzle position. This is where automated setups like the bl-touch come in handy. I have a 6x6 bed with 100 probe points on it. Takes a while to probe, but you only have to do it once in a while. Don't forget to double check at least a couple of spots on the other side after adjusting a corner. It takes a while to get right the first time, but future changes are pretty quick. Then adjust your Z-offset so that the PLA is a little squished on the bed. So if you were to measure it, you would have a line slightly wider than the nozzle. You get a feel for it once you see it. You should get the same width over the entire bed. There are actually test patterns for the bed that can help with that. PLA on a heated bed should never have adhesion problems once you get the leveling and z-offset right.