Product led growth for hardware startups?

I have worked in a number of hardware based startups, still do, and most have been product led or at least try to be. There isn't a one size fits all answer for what I think you are asking, and without more details it is unlikely anyone can give you great insights.

Generically, most hardware based companies today are really software services or data companies that have a hardware "interface" product. e.g. pick a consumer wearable product, what's really the product there? the hardware? or the users data? The answer is generally the user's data and insights that can be pulled from that data. So product led there generally starts with the insights and data, the hardware is just a means to acquire it.

My main point is unless you are selling primarily disconnected hardware, e.g. a non-connected toaster, you almost always are focused on the software services and data around the product and the hardware is just the bow you wrap it in to get what really is your product. So being product led for hardware isn't so different than SaaS or others. The one key difference is part of the user experience is the hardware, so you spend more time around optimizing the hardware and convincing customers why your shiny object is the one they need to buy. In the end though, usually those reasons to buy still boil down to the insights that come from the software. Hence you are still looking at all those growth metrics, engagement etc that most SaaS or software based business are watching.

If you are a truly non-connected or have severely limited software in the product then I'd have some different comments, but those are pretty rare in today's market.