What would you recommend to use as a beginner

I want to do more than just wash my car so what would you recommend as a total beginner more pressure washer and cleaners for inside and out

I already own a few

wash mitts

stjarnagloss bag

wheel cleaner

rinse aid

snow foam

pre wash and a bunch of little ‘testers’

Tyre brush and tyre shine(applicator too)

I’ve been looking at the karcher k2, k3 and k4 not sure which is better for this.