Im great at building hardware and software prototypes. Im tired of doing work for clients and I don't want to pursuit the single product > manufacturing - journey. Is there a business type that I can be in, to tinker along and build a profitable business?
A business by definition means that you will have to deal with clients. Sure, it could be a product or service or a mix of both but you can never get rid of clients. Otherwise you have no business.
The only exceptions are the types where you run a profitable blog, online courses, ads and make money through those but even they require dealing with your clients at times (e.g. buyer of a course) but the interactions will be limited and much less demanding.
But customers are always going to have dumb ideas, and you generally don't get to tell them to completely fuck themselves.
May I ask, do you think the situation is the same in data-science / IT -related fields, too?
web, apps, etc.?
Hardware as in electronic devices? computers?
Are they functional or just design mock ups?
Seems you have enough experience and expertise to lead a few people such as yours and give counsel to companies in the field of product prototyping.
Applied Minds is hiring. http://appliedminds.com/
Here's someone doing just that: https://www.smartpassiveincome.com/podcasts/how-to-get-paid-...