@Promethean75,
You can't force creativity. But music theory DOES help.
More important for guitar is that one needs good quality ones where the action is comfortable and the intonation keeps the guitar in tune throughout the fretboard.
The cost is the biggest issue as well as that age factor and the free time needed, ...especially when one is young. But don't let these factors alone make you give up as you grow older. Play specifically for yourself because inspiration for creativity is not something you can force. Learning the traditional 'classical' music through things like the Royal Conservatory (here's Canada's version, which you CAN technically use if you can get to the site:
https://www.rcmusic.com/
Look for book sales locally because many who have taken lessons will have many of these. Note that symphonies often have book sales themselves that include these. The libraries often have them too, not to mention that you can probably take them out directly from there too. I don't recommend taking lessons prior to your own investment to learn the basics or you are better on your own without it. On that site (as an example), if you get it, you'd want to first purchase SYLLABUS for Theory and Guitar. These tell you what you NEED to learn for each level/grade. They provide the music for grading and practice but are light on teaching. That is why you need the theory separately and given you already have familiarity with guitar, the theory would supplement your 'lessons' that correspond to the particular grading of each level.
Every musician is required to 'play by ear' and so it is not necessarily the virtue to address as you would still have this to work with regardless. I could go on but this is beyond what others would care to read. I hope this helps.
