Sadly, this is still a market that is meh. I'm in the same situation sort of. Want something to control my fans. I replaced my GPU cooling with the NZXT G10 and a water cooler, so it can't cool itself anymore based on GPU temp, etc.
The real problem is no device can read GPU, CPU, MB temps from every single motherboard,cpu, gpu on the market. there are too many variables, so usually the motherboard and gpu are the best fan controllers as they can read the temps right from the die.
The best solution most companies have now, is temp probes that you stick to various spots in your case to get temps and control fans that way. With a water cooler, there is no heatsink even to tape the probe to, so the probes are are a best guess at the most to temps.
The NZXT Grid+ comes a bit close, being able to read most CPU temps and ramp up fans that way, but is still limited to not be able read GPU temps and control certain fans for that. There fan profiles also only go down to 40% speed.
I'm almost looking at one of those manual ones with the sliders or knobs and just crank it up when I want. lol.
Idealy, I'd like a device that can read CPU, MB, GPU, even HD temps, and then apply certain fan settings to certain fans based on those temps. Copying lots of files, crank up the front fans if the HD temps rise. Rendering 3D fractals which are all OpenCL and on my GPU, CPU isn't touch, so ramp up the GPU water cooler and fan, doing lots of CPU photoshop stuff, crank up the CPU fans, leave the GPU alone. Sadly, I don't think such a device exists.