I've hired quite a few security folks in my time (some with criminal convictions) but my answer is an unhelpful one: it depends.
If you have a criminal conviction it's unlikely you'll get through the screening process with a regulated business (like banking, insurance, pharma etc) due to some 'out of the hiring managers hands' constraints those industries have. I've seen exceptions to this in the past, where a senior manager strongly advocated for the exception, but it's _very_ rare.
I've worked with several security people with criminal convictions in the past at non-regulated, FAANG and FAANG-like tech companies. They also usually have policies in place to prevent hires with criminal convictions, but the exception process there is easier, particularly in security teams where these convictions are more likely to occur in strong candidates.
The biggest concentration of folks with backgrounds like yours have been at security consultancies, in my experience. Combined with the experience you mentioned with bounties, that would be the place I'd spend most time looking. You might still get rejected from some, for example those with customers that require criminal background checks for employees or security clearance you couldn't get, but there are still quite a large percentage where you could find work. Personally, I've had conversations with external consultancies who say things like "I know you require criminal records checks on all our employees, which we're happy to do, but I want you know >50% of my team will fail them".
A couple of other things:
- No matter where you work, with your background there might be some kind of 'restriction' placed on what you work on and/or how you work (e.g. can't work on project Type X or must work from Office Y). If you do get through a process, ask about this before joining, as it might have an impact on how much you'd enjoy the role.
- Be open about your background. You sound like you would do that anyway, but the more open you are the better, you don't want this to be a surprise to people. What you're looking for is a strong advocate on the hiring team, so building trusting relationships with people will be important.
Don't be too down on yourself, you might have made some bad decisions, but you sound like a talented professional. The criminal justice system exists for people to serve their punishment and then move on with their lives. There are companies that will be delighted to hire you because of your skills. Your road may be a little tougher than for others, but that doesn't mean you can't end up professionally happy, fulfilled and well compensated.