I've never done that myself, but I backed an SDR device called Flipper Zero on Kickstarter some time ago, and I found their updates on the project status very insightful.
Through their posts, you can make an idea on how complex and how much work there is on developing, manufacturing, certifying and delivering a hardware device.
Through their posts, you can make an idea on how complex and how much work there is on developing, manufacturing, certifying and delivering a hardware device.
Link: https://blog.flipperzero.one/