I tried putting with a line, and ran into the same problem of not trusting it, but rather than realigning 3-4 times, I would over-correct with a push or pull, especially on the short to mid range putts. I’m better when all I see is a blank white side of the ball, sort of clears my mind.
I also found that I’m better off committing to a quick read than over-reading and being unsure. My read isn’t always right, but my stroke is better that way. 2 good practice strokes, then try to repeat the practice stroke when I’m over the ball. Trust the process and let the results be what they are. That being said, I’m still better off marking from 2-3 feet than trying to hurry and finish out if others are still out as I tend to rush my routine.
I play in under 3 hours solo or 3.5 to 4 hrs walking with my normal group that plays at dawn. Normally a small money game and a somewhat competitive atmosphere and not in a hurry, but faster than a tournament.
I grew up playing a lot w/ my parents who both play extremely fast, and who also will skip around to other open parts of the course rather than waiting behind groups if it’s backed up, so playing fast has always been ingrained in me. Though I played competitively in college, I struggled in slow rounds where I had to wait (which was most of them).
When I play a slower round, whether tournament or casual, I’m better off if I can keep my same routine once it’s my turn to play, but also to look around and enjoy the scenery if I’m waiting rather than watching someone else’s routine or over-analyzing my next or last shot. It’s still a struggle, but I’m working to get better at embracing the round, staying in rhythm, and enjoying my time on the course rather than stressing about the pace.