I have to disagree with your “janky” perception of my setup. (Thanks so much for the helpful definition)
I actually think the nice thing about the rig I use is that it doesn’t really require any “install”. I put the unit in the boat, run the transducer and cable and I’m done. It’s just as easy to pull it back out of the boat. I certainly don’t find it to be sloppy – there’s one cable with the extra length coiled under the seat. I wrap the safety retainer clip for the cable around the grab bar and then pull it snug against the side of the boat. The cable doesn’t get in the way at all – nice and neat. The unit and base are just sitting on the center hatch. If I need to access the center gear bucket, which I do regularly, I just fold the head unit down and set it aside. As I said, there is a bracket available I could mount that would allow me to snap the base securely onto the sideboard, but I haven’t felt that would improve my experience at this point. I’m perfectly happy with my "janky" setup.
As I said in my post, I don’t have a temperature sensor hooked up on this unit, so that’s not why I have my transducer in the water. I did a fair amount of research on this and other sites and found many reports of unhappiness with the sensitivity of through hull transducer installation. I definitely agree with Jim_MI on that point. I also considered mounting the transducer through a scupper, but that would still expose it to damage when I land the boat and it would be much more difficult to move or clear vegetation from the unit when on the water. With my setup, it’s very easy to reach around the side of the boat and place or move the suction cup once I’m on the water. I can tell when I’ve picked up weeds and it’s very quick and easy to slide the suction cup to the side of the boat, clear it, and replace it. This is also how I handle moving the transducer when in super shallow water or when landing. I can easily move the transducer, drag the boat across a sand bar or shallow area, and then put it right back in place in a matter of seconds. This would be much more difficult with a scupper mounted transducer, which would have to be accessed from the bottom of the boat. I can guarantee you the scupper mount would still catch grass and weeds.
So, I encourage you to enjoy your neat and tidy setup. I guarantee you that I have and will continue to enjoy mine, and I share it as a simple alternative to anyone who is interested.