You don't need to do a bootcamp (and I'd argue it would not help at all) rather you need to ship something and then layer that with previous non-programming job experience to demonstrate that you can deliver things as part of a team. My greatest value (as a software engineer) is in the non-code value I bring to my team. Given the choice between 2 candidates, 1 with only experience as a software engineer, and 1 with experience of non-programming jobs, I'd be giving strong consideration to the person with a broader range of experience. Leverage your non-programming work experience to show that you can deliver value.
Regarding passing coding challenges: coding challenges are a very lazy method that companies use to filter out candidates. Passing a coding challenge is easy and doesn't mean much (they're also just as easy to fail) so don't focus on them at all. Your focus should be almost exclusively on interviews, and you should work towards giving the interviewer as much confidence as possible that you'll be a valuable member of their team.
Also, don't assume that levels (junior, mid, senior) correspond to the amount of programming job experience you have. If you can ship code yourself, you're already mid or senior level at most companies.