I think part of it is that you're conflating writing music with sound design. They often go hand-in-hand but are two different skills. Kind of like programming vs (video) game design. For example, you don't have to design a flute in order to play one. Unlike synthesizers, most instruments can't change (much of) their sound. Organs are probably the most versatile in that regard, but they achieve it basically through brute force. (Traditional instruments do still have quite a bit of flexibility, but it's nothing when compared to a synthesizer; e.g. a violin is very versatile, but you can't suddenly make it sound like like a flute)
For learning sound design, first pick a type of synthesis (as others have talked about). Most people start with subtractive synthesis and it is by far the most popular. So much so that bits of it overlap into other tools that focus on different forms of synthesis (e.g. lowpass filters as part of a wavetable synth). As for plugins, you can't go wrong with synth1. It's free, does more than what you'll need to start (you can just ignore knobs until you understand them), and has clear labels. Start with an initial patch (should be a basic sine wave IIRC) and build up from there.
Learn what the different components actually do to the waveform. You can't think of it like "this makes the sound more like this" since how it changes the sound depends on the rest of the parameters. This is probably why you end up "aimlessly manipulating ... knobs and switches".
For actually writing music (not just tweaking your bloop sounds), Ableton has a fantastic interactive guide [0] that takes you through everything you really need to make music. Everything else builds on top of that and is arguably unnecessary. It also includes great examples. There is also practically infinite information out there around writing music. Go get some.
While focusing on writing actual music: don't be afraid of presets. There's nothing wrong with using them, especially if you are just learning. Nothing in music is 100% original. At the end of the day, all that matters is that it sounds good (and you're not blatantly copying others' work). You can start to use your own sounds once you learn more about actual synthesis. As you start to learn more synthesis, try finding a preset that is close to the sound you want and then tweak it to your liking.
As far as DAWs, don't assume there is "one perfect DAW" for you. FL Studio might just not suit you. While all major DAWs should be able to achieve the same things, they often go about it differently. Depending heavily on how you want to work, some will be harder for you. You'll likely end up learning more than one eventually, so try out a few. Once you find one that starts to click, STOP SWITCHING. Stick to that one as long as you possibly can.
REAPER [2] is a great option for beginners since it has very generous pricing and trial. However, it's not just a "beginner DAW" -- it is fully capable professional software.
The key to making any progress learning is focus.
[1]: https://learningmusic.ableton.com/
[2]: https://www.reaper.fm/
Addendum: I mentioned learning what knobs do to the waveform, but I never explained how. There are plenty of options, but the most basic way that you can set that up right now for free is to grab REAPER, synth1, and some free oscilloscope plugin. This very basic setup will take you extremely far in learning synthesis.