ᐅ Insulating a Wall in an Unheated Garage: Are Silicate Boards a Good Option?

We want to insulate an uninsulated interior wall in the unheated garage (concrete hollow blocks, the gray blocks with hollow chambers, roughly 24 cm (10 inches) thick with about 1 cm (0.4 inches) of exterior and interior plaster each, built in 1989, and presumably a very poor U-value) by ourselves. On the other side of the wall are the kitchen and bathroom (so they share this wall with the garage), which makes insulation sensible given the poor quality of the blocks. The garage tends to have higher humidity (unheated and with a floor sloping towards the rear garage door). During heavy rain, water dripping on the garage door runs over to the lower rear garage door (ventilation opening at the bottom) and drains away.

Are silicate boards suitable for insulating this wall in the unheated garage? Or what would you recommend? The roof is insulated and covered with drywall.