I've always enjoyed the dedicated hardware track at All Things Open (Raleigh, NC, USA, October). They also partner with an organization called RIoT that has a lot of resources for startups and typically do a demo night, among other things.
I would love this. Organizers get on this; with the rise of things like JLC and PCBWay hardware hacking culture is making a resurgence, and I suspect there will be many new makers trying to start small companies, similar to the SaaS boom. We have tons of these in the software world but, as evidenced by this post, not so much for the hardware scene.
Many music conferences for new music products (including both software and hardware) are open for those bootstrapping a hardware business. You can set up a booth and demo your product to create interest for when the hardware is released and to take pre-orders or just to get ideas and feedback for features/design. Might even connect with a larger company that wants to adopt your product. Some of the conferences may offer some sessions on bootstrapping a business. Some of the larger ones are Superbooth, NAMM, Musikmesse, and AES, but there are lots of smaller ones also such as SynthPlex and Ableton Loop. Knobcon might be a good one. Not sure if MoogFest still exists since Moog was bought by a mass-market conglomerate.
https://riot.org/event/riot-iot-demo-night-2023/
https://2023.allthingsopen.org/schedule/
It's not exactly what you're looking for, but it's a great opportunity to network with other people in this space.