will practicing improve my guitar playing?

You are trying to move too fast. we have all been there. Slow the song down to about half speed and play it that way until you can do it perfectly. This will build the muscle memory needed. Then you will be able to play it correctly at normal speed. When you try to practice something too fast you make mistakes, and when you make mistakes you are literally training the brain to play mistakes.

Yes, as with any other skill there is.

It depends. If you can play the guitar at the level needed and you are practicing correctly then yes.

Added, I see that a few months ago you were asking a question about "strumming patterns" suggesting that you are very much a beginner. If you need to ask about which direction to strum in when playing a song then you haven't really got the basics of playing yet (NOTHING wrong with that, after 40 years I sometimes think I haven't either). But, if you are trying to learn to play something that requires skills you just don't have yet then you're wasting your time - you can't "practice" something you can't do: you need to learn how to do it and then practice. A really extreme example would be a beginner violin player trying to "practice" Vivaldi's Four Seasons. However much they practice it they won't ever be able to play it because they haven't learn the skills they need.

You need to learn the skills and then apply them by playing real music, not try to play real music and hope you'll develop the skills.

Only you know whather what you are trying to play is within you ability or whether you're attempting something beyond you.

yes its called muscle memory