Volume pedal impedance

guitars need high impedance pedals.

I’d suggest getting an expression pedal. Set it as volume. One less cable and the ability to place it in multiple locations in the signal chain.

It can also function as a wah pedal. WAY more versatile than a dedicated volume pedal.

In most cases I would go for an expression pedal as Ruefus suggested.

If you do want an analog volume pedal then it depends on where you want to use it. For a pedal between the guitar and Kemper you want a High Impedance pedal as BillyNoSocks said. However, if you want to use it later in the signal chain (say after the main outputs then you need Low Impedance. It depends what you want to achieve. Straight after the guitar works like the guitar’s volume knob and has some effect on volume but also has an effect on gain of the amp. Depending on how dirty the amp sound is this might have a huge effect on volume or it might have almost no effect on volume but control the amount of distortion allowing a constantly variable Clean/Dirty sound. I like this and use it a lot BUT my guitar already has a volume knob so I always put my volume pedal late in the signal chain (after the stack or right at the output) where it has no effect on the gain characteristics but just controls how loud or quiet the sound is.

With a volume pedal you need to unplug and move the pedal to change how it works. With an expression pedal you can save the position on a rig by rig basis. You could achieve something similar by placing the volume pedal in an effects loop but this would then effectively waste an effect block that could be used for something else.