Breaking the Loop
You can name every chord in the key. You know what a secondary dominant is. And then you pick up the guitar and out comes the same progression you have been playing for six years.
That is not a knowledge problem. Theory, the way most of us learn it, gets stored as facts — the vi chord in C is A minor. Playing does not run on facts. It runs on reflexes, and your hands have a far smaller vocabulary than your head does. On guitar you might know fifty chords and own eight shapes. Under the mild pressure of actually making a sound, the eight shapes win. Every time.
So the fix is not more theory. It is operations — small, specific things you do to the chords you already play, until doing them is itself a reflex. Below, put in a progression you catch yourself playing. The page will tell you what it is, then hand it back to you thirteen different ways, on your instrument, with the sound of each one.
None of these require you to learn a new chord. That is the point.
C G Am F,
Am F C G, Em C G D. Slash chords and sevenths are fine.