Does having founder experience affect the resume negatively?

I'm an electrical engineer with more than 10 years of experience in the fields of systems, integrations, embedded systems, robotics, and other cool stuff. I also have expertise in fields like cybersecurity, project management, and various other skills and tools I have learned on my own that enhance my overall work.

Around 2 years ago, I left my job, which might have been a mistake, but I left because the environment was so toxic that it was mentally exhausting on top of the stress of doing technical work. It's a shame because I really liked and enjoyed the work itself, but the people ruined it. I noticed, talking to some friends, that a lot of robotics companies somehow manage to hire difficult middle managers who turn work into hell.

I took 4 months off after leaving to relax, as I was burnt out. I had worked more than two years with zero vacation and even worked on holidays (I was never paid for my vacations or overtime, by the way). After this much-needed four-month break—during which I even noticed some grey hairs colored back after relaxing a bit—I made my personal portfolio showcasing my great work, updated my resume, and linked parts of it to my portfolio to verify my experience. Then I started a company to do contracts in the same field. Whether it's due to the bad Canadian economy or failing to acquire proper leads, I barely got any substantial contracts. I even had some great ideas I shared with investors, but none were interested.

So, after almost a year, I decided it was better to do damage control as I was burning through my savings and look for a full-time job in the meantime. Since last October, I have been applying for jobs that either completely fit my resume or most of it, and I rarely apply randomly. For many applications, I write cover letters too. Out of hundreds of applications, I had only two interviews. In the first one, the interviewer was interested that I was doing entrepreneurship, and I was honest about it, and they liked that. However, they never called back. The other interview was with the government, and Canadian government jobs take forever. Not to mention, they require a security clearance that might take nine months to get, so it's not really an option to rely on.

This made me wonder, talking to a friend, if having "founder" on my resume is really a negative thing. Even if I remove it, there will still be a gap that I will need to explain, and I was technically working for myself despite the outcome. Secondly, what other job sites are there besides the very popular ones? I feel the popular ones are flooded with applications and have auto-screening out, so no real humans actually read them, which might be another explanation for this situation. I know HN is mostly software folks and software world is probably more fixable but still it's great to get some feedback.