Definitely believe regulation burden should be proportional to impact.

Also, for those small cases, why not put responsibility (for any harm) more directly into both the customers and producers? For example, if a producer of a new low-volume product somehow manages to get a lot of waste packaging into the environment, they could be held responsible and pay a fee, or probably who discarded was the consumer, so the consumer in this case should be held responsible. I get that large corporations should be held to higher standards, and take stronger preemptive measures and follow stricter compliance rules.

I think the same should apply for all sorts of regulations, like electrical safety, radio emissions, etc.. If you're designing and selling a small product, you can and should take responsibility for what happens to it (in the case it is found your device bad design/construction itself caused injury, of course). Maybe the only thing you should be obliged to do was put a large sticker like 'WARNING: Prototype-class device. By opening you accept some RISK OF INJURY from device. Return to source if terms not accepted: (...)' -- that is, both you and the consumer should share some responsibility for trying something experimental.

Probably the overwhelming majority are completely harmless low-voltage devices.

In general, I think outcome-based and performance-oriented regulation is something that should be more widespread. Like, there should be in the worst case two options: (1) You follow a strict set of rules and guidelines that dictate how companies in your industry type should operate (specially important for high-risk stuff like nuclear plants, large civilian housing buildings, etc.); (2) You (instead) take increased resposibility for outcomes of your activity (products, devices, etc.), being liable for any damage at an increased rate.