A guitar made out of clay?
I now have a third guitar in playable condition. My late brother was a bit more than eight years older than I am. He bought a Teisco Audition electric guitar in, at a guess, 1969 or 1970. (It looks like this one.) His best friends were all musicians, and they had a band named Otto, which my brother managed while they were in high school and helped out as a roadie, but he never learned how to play himself. I don't know why. (The band was named after the way my brother pronounced "auto.")
Several years after he bought it, when I was ten years old, plus or minus a year, my brother saw some of my friends and me trying to figure out how to play guitar. He gave me his. I asked my parents for lessons, but nothing came of it. In any case, I didn't learn to play it, either.
Time passed, and my oldest niece, my sister's daughter, said that she wanted to learn how to play guitar. I gave my brother's old guitar to her. In the years that passed, I imagined that my niece kept it with her other guitars.
To my dismay, I recently found out that it has been living in my sister's basement under less than ideal conditions all this time. My niece clearly didn't want it, so I took it back. I've cleaned it up and repaired the headstock. It can be played again, and I've been doing some of my practicing on it. I like it.
I'm still practicing several times per week and usually going for an hour or more each time. My best guess is that I've been practicing at least seven hours a week, and I'm still making slow progress, enough for me to keep trying. My finger strength, independence, and ability to stretch them have much improved. My ability to keep time has improved. (It's still not good, but it has improved.) I've been working on ear training, but that is still sad. My ability to mute unused strings has improved.
My chording speed gets better at a glacial rate, but it is getting better. I can make E-shaped, A-shaped, C, and D barre chords, fairly slowly, and I still sometimes have to reposition my index finger to make every string ring out, but I can make them all over the headstock side of the neck. G-shaped barre chords still elude me in that I mute strings that shouldn't be muted.
I've been studying the CAGED system and learning the octave shapes. I know them, but they aren't automatic yet. I still have to think about them. I've also been working on memorizing the notes of the fretboard. I've been making progress, but again, they aren't automatic.
I put these tuning machines (which I got for about $55) and this nut on the cheap Glarry guitar. It was educational, and the guitar has good tuning stability. It more than doubled the price of the instrument, but it is still cheaper than a bottom of the line Squier. I think it is now good for learning, and it is more comfortable than my mahogany guitar for long practice sessions. I've also monkeyed with the relief, the string height, and the intonation, so I've already got quite a bit of education out of it. If I ever get tired of the guitar, I can always take the high quality tuners back out of it. Or, if I ever get good enough to warrant it, I could play Dr. Frankenstein with the thing and use it for experimenting with different pickups and electronics.
You're comment about playing Dr Frankenstein immediately made me thing of the Edgar Winter Group. :-)
The great thing is, either way it works.
Why do guitar bodies or necks cost more than complete guitars?
I wouldn't stress too hard on learning the notes (as long as you can figure it out pretty quick, it's usually NBD). I don't remember the particular context of me saying avoid hipshot but I can almost guarantee it was "avoid hipshot d-tuners" because they require a good ear to get working properly).
re: bodies/necks being more than complete guitars. it really depends on the brand and customizations. warmoth is going to be pricy AF but they are absolutely gorgeous. Noname pieces can vary between "this is mostly sawdust held together with glue and hope" and "this is warmoth without the stamp on it". btw I would suggest you check out https://www.guitarfetish.com since the lutherie bug seems to have caught you. I am still in the process of making my own as well, mostly for the benefit of custom electronic setups that I want (tl;dr is a tele with a humbucker in the neck and a singlecoil-sized humbucker (rails) in the bridge so that it is visually like andy summer's tele in the police but with the dual humbuckers can be coiltapped so that it's S/H or H/H or H/S or S/S. Biggest problem so far has been finding a flat or flattish neck that will work with it. I learned on a spanish guitar and electric bass and so I'm used to really big necks with wide radius or no radius at all.
On the subject of theory, you may enjoy Adam Neely's youtube videos.