My putting stroke ain't perfect. Marking a line on a ball only makes me second-guess if I've got the line aimed accordingly, based on the perfect stroke, which I've already admitted that I do not have.
I've played the game for 30 years, at a fairly high amateur level. And yet I know my putting stroke isn't perfect but for maybe 1/3 of the time.
Doesn't mean I'm a horrible putter. It means I've adjusted to my tendencies under those situations, that I've not obsessed over the nth detail. In other words - I've simplified the process.
Putting is all about finding a spot about a foot or two on the green... a blemish in the grass, or an old repaired ball mark, and stroking the putt with the right amount of pace to go about 18 inches beyond the hole on that line.
It really doesn't need to be more complicated than that.
If your pace sucks - your putting sucks. If your pace is good, generally speaking, your putting ain't that bad, because you're usually leaving yourself with a short one to tap-in.