Initially my rails glided smooth with the shipping oil they came with.

Internet said, "nooo wipe off the shipping oil, use proper lube" , so I wiped it off with isopropyl alcohol and lubed it with bicycle grease. The ball bearings wouldn't roll anymore. Rails moved, but didn't glide.

Internet said "oooh you want PTFE metal-to-metal grease", so I dismantled the rails and bathed them in an alcohol. When clean, the rails glided. As soon as I used this grease, the ball bearings wouldn't budge anymore. Move, but not glide.

Internet said "oooh you used the wrong lube, you want PTFE-free white lithium grease", so I dismantled the rails and bathed them in an alcohol bath again. Without any lube, the rails moved smooth again. I sprayed them very sparingly with the new grease, and whaddaya know the ball bearings wouldn't roll anymore again.

Realising that the internet knew shit about shit, I left them as is and moved to the next step of the printer because I knew that perfect is the enemy of good