I will plaster the outside and inside with facade putty, maybe go over it with a foam roller to give it texture, and paint it with facade paint.
I started building a garage to learn how to work with these blocks. Then I'll build a house, and maybe I'll chamfer each block and just paint it with vapor-proof paint.
In the picture Blocks with chamfered edges. External finishing is not even required, just paint.
Over here, they started installing closed cellular foam board to the exterior of some builldings then using some kind of s cement/grout looking stuff to spread over them.
Gives it a sort of a stucco look but with great insulation value.