Can you upgrade the 4x18 gauge wires? RGBCCT strips need 6 wires. BTF Lighting makes good products. https://www.amazon.com/BTF-LIGHTING-Multi-Colored-Silicone-Coating-Waterproof/dp/B07KQVGJ5F/ For undercabinet / overcounter applications, placing LEDs in aluminum tracks makes for a much better finish look. https://www.amazon.com/gp/product/B078J143MN If you use the aluminum tracks with diffusion covers, there's no need to buy waterproof strips. For undercabinet kicks, I place waterproof LED strips directly under the cabinet without using tracks. A router can be used to cut a groove under the cabinet to keep the strip flush.

I placed 5x18 cables, which allow me to use RGBW strips, but not RGBCCT strips. Futureproofing is hard - who knows what comes after RGBCCT?

With 4x18 wires, you can still use RGB strips without the white LEDs, but making white light with RGB LEDs is not as efficient as using white LEDs. You could also use "dreamcolor" LEDs, which only need 3 wires and allow for individual control of each LED, but they're more expensive per LED and require different controllers.

There's lots of choices for power supplies. I've had good results with MEAN WELL supplies, which are UL Recognized (UR logo). UR is the appropriate safety registration in the US; UL listed products are required to be complete products, and a power supply is a component.

The more closely together the LEDs are spaced on the strip, the more even the resulting light will be. I've used 60 LED/m strips, as 30 LED/m strips will look like a series of dots. You can even get 90/m, even 144/m. 12V LED strips can only be cut every 3 LEDs, which becomes an issue if you're trying to make shapes with the strips. If you're careful, it's possible to fold LED strips to make 60 or 90 degree corners, or cut the strips and solder wires to make turns at the cut boundaries. There are also connectors for 90-degree corners, but you can only place these at the cut boundaries, which limits the geometry you can follow. 24V LED strips can only be cut every 6 LEDs, so they're even more limited.

Dreamcolor LEDs strips don't generally have these cut restrictions, they usually have cut marks between each LED. However, they run on 5V power so they need 3x-to-8x more current per LED. This can cause substantial voltage drops along the length of a strip, so you may have to run booster wires alongside the strip, periodically connecting to VCC & GND.

For LED drivers, what you use depends on how you intend to control the lights, whether DMX, ZWave, Zigbee, or something else. In drivers for LEDs, look for 500Hz to 2kHz PWM controllers, so as to avoid flickering. If you plan to ever take video of the result, in fact, this is a mandatory feature, otherwise they'll flicker like mad in any videos.