Cables disks are definitely trickier to setup than hydraulic brakes.

Nowadays hydraulics come out of the box pre-bled with hose already installed, and you may just have to trim the hose to length (if at all) and break in the pads. Plus the fact that they are a completely closed system means environmental factors hardly effect performance besides maybe extreme temperatures.

Cables disks have to be setup like any cable actuated brake system with the added factors of disk brake setup. You still have to cut cable and housing to length, align the brake, get rid of as much play out of the system as possible (by cable/housing stretching & adjusting pad clearance), and break in the pads. The biggest problem with cable disks is that pre-stretching the cable (partially pulling the piston arm) to get a good brake lever feel (shorter and stiffer lever pull) actually dramatically reduces the stopping power. It's a bit of a tightrope to allow full piston actuation (and maximum stopping power) and good lever feel. Pad clearance, pad type, rotors, cable and housing length & routing, & lever brand all play a factor. Get them all dialed and you can setup a cable disk to lock up with your pinky finger.

I went through a similar experience being underwhelmed with cable disks having tried Avid BB5s/7s, and both the TRP spyres and Hy/Rds. Then I just trial & errored my way into getting the best setup I could.

• For cable disks, metal pads will never be as powerful as organic or semi-metallics. I came upon SwissStop E-type pads that are a semi-metallic/organic pad formulated for e-bikes and road disks. They are a little pricey but they last longer than full-organic pads and the stopping power is just as good in the wet. If you look on ebay there are also some more affordable semi-metallic pads from TruckerCo and similar aftermarket brands.
• Compressionless housing is a must. Looks like kidsafe is running Jagwire elite links (?) which are pretty trick segmented compressionless housing similar to Nokons /iLinks/Bungarus. These are pricey at $60-80+ a set, but there are also cheaper options (Jagwire makes non-segmented compressionless brake housing).
• Stock rotors that come with cable disks are almost always garbage (especially TRPs). Shimano RT-66s or above work good with organic pads, and even better with broken-in semi-metallics. Also, use at least a 160mm rotor front and back for cable disks. 140s are really only for better modulation with rear hydraulic road discs. Since we're talking cable disks you already have modulation in the brake lever.
• Cable/lever pull is probably the most important. Like I mentioned previously you want to get as much of the piston travel as possible while still having a decent lever feel. The trick I've found is to make sure cable and housing is really settled in to remove as much slack in the cable without shortening the piston travel. Third hand cable pullers are great for this. Then it's a matter of adjusting the pads as close as possible without getting rotor rub.
• Lever brands make another big difference. 1st gen SRAM and Campag levers and older (non-shifter) road brake levers don't have enough cable pull for most cable disks. Current SRAM and Shimano are the way to go.

fyi, I'm personally running TRP HY/RDs with SRAM Force 10speed levers, Shimano RT-98 rotors, Swisstop Disc 15 E-type pads, & Aican compressionless housing on my commuter. When I went out on my first ride with this setup I nearly endo'ed more than a couple times. I'm pretty decent at nose wheelies now.

Apologies if I'm preaching to the choir. Hopefully this post will help some disenchanted cable disk brake users.