My best advice is to just focus on one thing at a time. Learning music theory is important but that should be something you learn once you're better at guitar and you're able to play it without struggling to move around most of the time. Or at the very least take a music theory class if you're still in school and improve on it later on.
As for exercises there's a whole bunch of them, the spider exercise is a great one to start out with but there's some others to try out. I usually do these 3 other ones listed down below. Keep in mind that for all of these you should use a metronome and make sure you're doing it slowly. Only increase the bpm when you can do these with very few mistakes.
1. Going through each scale mode
Pretty self explanatory, go through each scale mode and play 3 notes of that scale per string. If you don't know the scale modes that's fine just search up tabs for each of them. If you wanna challenge yourself, you can try moving diagonally instead of just up and down.
2. Idk what to call this one, it's just similar to the spiderwalk but on crack
I suck dick when it comes to explaining stuff but basically you plant all your fingers on the first 4 frets on the high e string. Start off by going up & down on the first two frets, then go up & down on the first and third frets, then the first and fourth frets. After that you do the same thing, this time starting with the second and third fret. The last part of this exercise should involve going down the third and fourth fret. Make sure to keep any unused fingers glued onto the high e string. This one is REALLY good at building dexterity but it leaves my fingers sore as fuck.
3. C major arpeggios
You don't even gotta know what an arpeggio is or the c major scale really. I only call it that because you're just going through the arpeggios in the c major scale, all you gotta do is just play these tabs. This one is the hardest one on the list imo and takes me the longest cos it can be tricky, especially at higher speeds. It's really good at building coordination between your two hands, finger dexterity, and picking speed. I cannot recommend this one enough dude, it takes a while to learn but it's worth it.
Here's the tabs: https://imgur.com/a/VJcagIp
Quick little side note: I usually don't recommend learning songs just cos they're not as useful when it comes to improving your skills, but there's one that I play that's REALLY good for practice called Fracture. I can't play the whole thing yet just cos it's so damn hard but if you wanna have fun testing yourself, you might as well give it a try. Again, make sure you keep the bpm down, you wanna make sure you don't build any bad habits.