There ain't no glue for PLA

[SimEyeSee]

You probably want something like plastic cement. @Olias mentioned it in the link below.

In the case of cement, you’re using a solvent-based material that will literally dissolve the two materials and weld them together.

Glue "moat" for joined parts

I guess the answer to that also depends on whether you’re intent on using actual plastic glue, such as Cyanoacrylate, or plastic cement. In the case of crazy glue, you’re adding material to create the bond so a channel might help. In the case of cement, you’re using a solvent-based material that will literally dissolve the two materials and weld them together. So in that case, you want to do the opposite and have not only no channel but print on a smooth plate where the bonding surfaces will mat…