Never level your bed again. Throw away your sheets of paper and loc-tight those bed levelling screws! I've design a three-motor bed levelling gantry that should work with most cube-style FDM printers and uses most of parts that you're probably already using in your current two-motor setup.

What you'll need:
Five 8mm linear rods/bearings/clamps (your printer probably already has four):
Rods: https://amzn.to/3NKMY6k
Bearings: https://amzn.to/3ztbCnE
Clamps (x2): https://amzn.to/3Hhhm5G

Three 8mm threaded rods/bearings (your printer probably already has two): Rods (w/Nut): https://amzn.to/3SvjFYz
Pillow Bearings: https://amzn.to/3mELiPR

Three stepper motors:https://amzn.to/3MMx8H1
Three 8mm timing pulleys: https://amzn.to/39jLilg
Three 5mm timing pulleys: https://amzn.to/3xJRY5p
Three 200mm x 6mm GT2 loops: https://amzn.to/3NQ4Yfu

Three 10mm threaded steel balls: https://amzn.to/3ty026K
Three round countersunk magnets: https://amzn.to/3QkNjhu
(note that these claim to be '12mm' magnets but are actually 15mm. You want a 15mm OD magnet for this build)

And then you'll need an assortment of m5 bolts and boat nuts, an m4 bolt for the threaded balls, and a 2020 90 degree angle of some kind for the bed.

For the basic setup you'll need to print:
1x Double Bed Mount - Short (or long depending on your bed platform size.
1x Double Bottom Mount
1x Double Top Mount
1x Triple Bed Mount - Left
1x Triple Top Mount - Left
1x Triple Bottom Mount - Left
1x Triple Bed Mount - Right
1x Triple Top Mount - Right
1x Triple Bottom Mount - Right
3x Cap Magnet Mount (or Straight/Corner mount if you are building a square bed frame)

00:00 Intro
00:34 Two Motors are Not Enough
02:28 Triple Bed Levelling is Kinda Hard
04:05 Ball and Cup Mounts, Cheap Linear Rods
06:44 Bed Platform
07:48 Electronics and Tilt Adjustment
08:56 Conclusion

All 3D printed parts can be downloaded here: https://www.printables.com/model/2250....

Disclaimer: The Amazon links above are affiliate links to the specific parts that I purchased at full price. I receive a small percentage of the sale when you use those links - and I appreciate it if you do - however please use what is most appropriate for your specific build.