Purple “School Glue” is all you need. It’s cheap and if you work in an elementary school, free for the bending over and picking it up. I’ve got a life time supply from teaching for a mere 4 years.

Lubrication is kind of an issue. You want to oils over grease. And only a thin coating. You will find that lubricated rods and rails attract dust. A lot of dust with kids and pets. And that dust is VERY abrasive and will chew up the seals on you bearings unless you are constantly wiping and relubing. So, this is a time when less is more.

I use a SuperLube silicone grease to fill the bearings before assembling them onto the rods for my Mk3S. They have wiper seals that are meant to wipe the linear rods as they move and hold the grease in. I never oil those rods. The dust they attract will destroy those wiper seals in short order. I do, however wipe the rods with a dry paper towel before I print. In the 8 years I have owned the machine, I have replaced the bearings just once after about 4 years.

The little Bambu A1 Mini I have has open bearings on their linear rails and rods. Those require wiping clean and relubing with a special high tack oil on a scheduled basis. And yes, they are filthy when I clean them.