When my Ender 3 S1 (not plus) had bed leveling issues, the problem was caused by backlash on the Z axis. It’s important that the Z axis be just loose enough that downward motion is driven by gravity. If instead the Z screws have to “pull down” on the gantry, then the height will be too sloppy for ABL to make fine adjustments.
I briefly considered using Klipper to make a clock that prints 1 layer per minute, but gave up after realizing it’d be unreadable after the first hour: