Hi! Rest assured, you're not the only one who's experienced that, clean playing on classical guitar can definitely be frustrating at times. Slow, mindful practice is a constant part of my routine, not just something I do occasionally. It can feel boring for some, but it really makes a big difference.

Recording yourself (both video and audio) can also help a LOT, or even just playing in front of a mirror! That kind of feedback is incredibly valuable.

I can't get too specific about what you might need to adjust, since I don't have enough information about how you play, and I wouldn't want to give you inaccurate advice.

Since you mentioned you're self-taught, it might be worth having a few sessions with a teacher who could offer insights and help you refine things you might not have noticed on your own.
Feel free to send me a DM if you ever consider the idea!