I have as many questions as answers. I also got my first guitar in 1993. I've owned more than a few since. A couple of Fenders, an LTD, a bunch of no names.
I'll keep it simple - what kind of guitar did you buy and how much music experience do you have?
Because ultimately it seems like you're insecure about playing the instrument and allowing yourself to get hung up on the technicality of it all to avoid the initial learning curve. Or at least that what this thread reads like. If it's a brand new instrument then it's not going to be unplayable unless you bought junk at a flea market. The difference between an out of the box setup and a pro setup is negligible in inexperienced hands. To tell yourself otherwise is just making excuses. A professional setup will make the instrument slightly -
slightly - easier to play technique, but it won't make it sound substantially better or make it any easier to learn.
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Strings are ultimately a matter of personal preference. The main factors are the gauge and the winding method (round, or flat / ribbon).
Smaller gauge strings like .009s are easier on your fingertips and require less effort to bend - but due to their thinness they're also more prone to snapping. They're a lot more popular for flashy electric guitar leads.
Heavier gauges will hurt a bit more but give you a more robust tone and will generally sound better for longer.
As for the winding, the most common are round wound strings. These are the bigger / lower strings in a set. They're built by wrapping a wire around the string and depending on the shape of that wire you get different tones and feel. The round tone is generally brighter and a bit more abrasive. You can actually feel the ridges as you run your finger along the edge of the string. It's also necessary if you want to do something like a pick scrape.
Flat wound strings are just as they sound. Rather than wrapping a round wire around the length of the string, the wire flattened before wrapping. This results in a smoother feel and darker tone. It's a lot more common in jazzier styles. It's impossible to pick scrape flat strings. Very smooth and bass-y.
Personally, I keep flats on my basses and rounds on my guitars .010s or .013s.
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As for hiccups with tuning it could be a variety of things. If you actually had a problem with the nut the strings would be breaking at that point rather than sticking and jumping while tuning. It's far more likely that the strings haven't been fed through the bridge properly and are being pulled into place by tightening the tuning pegs. This is not a defect in the instrument. It should stop once the strings have moved into proper position within the bridge / under the pegs.
This is also something to be aware of if you're planning to change strings yourself.
If you have the traditional acoustic bridge setup you have a series of 6 pegs that hold the strings within the bridge. If there is too much string under that peg it's going to cause jumps when first tuning. Every instrument is slightly different and it's a matter of experience to figure out just the right length to get it working smoothly. Also make sure to pull the string tightly when restringing your instrument to maintain tension within the bridge and avoid slippage.
As for action I honestly wouldn't worry about it. Most acoustic guitars do not have an adjustable bridge so if you decide you need to adjust the action that means the truss rod - and that can only adjust so much. The easiest way I learned to check your action was to press down on the 1st fret of the lowest string with one hand and the 12th with another and eyeball the gap between the string and the frets around the 7th or so. Ideally that gap should be about the thickness of a business card. If it's too low you're likely to get buzz when playing an open string, too high just means a bit more effort when fretting a note.
As for humidity - acoustic guitar humidifiers are a thing. Some of them look like a tube that you slip into the instrument, others sit within the sound hole. There are lots of options -
https://www.amazon.ca/s?k=acoustic+g..._relevancerank
I can't comment on them more than the fact that they exist though.
Ultimately though, the most important thing to remember is that 95% of your tone comes from your hands. Rhythm comes from your heart. Melody from your mind. The instrument is really just a tool to accentuate those elements. If it's not within you, no piece of gear will change that. It's not fun to accept that you need to actually practice in order to play what seems like basic parts, but we all had to go through that process.