Provided you have the CP2K version (4.1 for example) having KPOINTS capabilities, you can use the KPOINTS section (https://manual.cp2k.org/cp2k-4_1-branch/CP2K_INPUT/FORCE_EVAL/DFT/KPOINTS.html).
On the other hand, CP2K does well with Gamma point (1x1x1 kpoints) calculations when you model a sufficiently large unit cell (check cp2k google forum).
If you have a specific convergence issue, you may also seek help in the active CP2K forum.