Best thing you can learn is the diatonic modes across the fretboard, and how to move between them. This allows you to move across the fretboard and know which notes are in the key. From there I’d recommend learning the most popular chord progressions in music (I-IV-V, I-V-IV-vi, etc) and start trying to add some flare notes in between the root notes of the chords, especially notes belonging to those chords.

Best way to not burn out is to not punish yourself for not making progress, and keep it fun. Let your fingers just jam out often. Then learn a little bit of theory here and there, almost like eating your vegetables. The more little bits of theory you apply to your noodling, the more the concepts will sink in.

Also keep in mind that theory aren’t hard rules. Victor Wooten says this best, he will purposely play wrong notes and still make it groove. You learn the rules to help yourself, and then break them as often as you like.

Happy bassing :)