I relate a lot with this. Especially cables--what an absolute nightmare, especially when you need to interface with commercial devices that have standardized on a different cabling standard!

I have learned about Mini-PV connectors, which are compatible with P=2.54mm headers and do not loosen up over time: https://www.mattmillman.com/info/crimpconnectors/dupont-and-...

> When I first saw a commercial install made of random Amazon modules, I thought "They shoulda made a PCB" and I had all these ideas.... but then I realized that when the random Amazon modules breaks, I can swap it in a few minutes, and fix it later if I want.

I can see this, and I've definitely created custom circuit boards for devices that I only need one of & would be straightforward to build with random modules.

But at the same time, for a commercial product or a product where quantities of > 10 exist, making a circuit board makes a lot of sense, introduces a lot of reliability and saves significant cost. It's really not hard anymore to make a PCB, and there's so much opportunity for error & poor connections when assembling things from Amazon crap.