Hi, I'll try and help here by explaining my situation and how I found work.
I was in a similar position after spending 3+ years in prison for a sexual offence. When I left I was given all sorts of advice from various people and organisations on what to/not to say or put on CV's etc..
I had to sign on for the first time in my life for the first few months, in that time I started applying for various jobs including warehouse work and kitchen jobs. I was also liasing with my probation but I didn't find them helpful at all when finding work. It was all down to disclosure and what should or shouldn't be said.
My second interview resulted in me actually being offered the job as a kitchen porter, after I disclosed that I had a conviction for a sexual offence. However the person who made the decision to employ me had been a bit hasty, as when her superiors got to know this they overuled her and said I couldn't be employed. This can be a problem. You may come over well in your interviews, but when the final decision is made by someone higher who hasn't interviewed you, the decision can change.
Regarding the gap in the CV, you may have to fudge this a little bit. Where there is a gap inbetween finishing your last job and being released from prison, I simply put I was in further education. Whilst I was in prison I gained many qualifications as I was in permanent education and work all the time. So on my CV I just put further education and listed all the qualifications I had gained. Obviously I don't know your circumstances and whether you actually did education, but certainly look into that aspect of representing your CV.
After my rejection after my second interview I got a bit wiser. The next kitchen job I went for I got to the second interview stage. At the first interview I was simply asked if I had any convictions to which I said yes and gave them a brief explanation of the offence and prison time. Unfortunately I didn't get this job, but at least I gained confidence to getting the second interview.
I then took part in a sector-based work acadamy run by a pub chain which guaranteed an interview upon completion of the course. I checked first whether they employed people with convictions and they did. After completing the 4 week course I applied online for a job with this company and one of the questions asked if I had a criminal conviction and what was it for, to which I answered 'yes, would be prepared to discuss this should I get an interview'. At least you are not giving too much away at this stage. When I got to the interview they didn't actually ask me if I had any convictions so I didn't mention it. I got the job and I was employed as a kitchen assistant. I left prison November 2017 and I started this job in May 2018.Although it wasn't the best job in the world and the hours were a bit unsociable, it was a job. Once I had this job I kept looking for something better as I knew I stood a good chance as I was in current employment.
I then saw a warehouse job on Indeed and applied online for that. I was not asked on the application form if I had any convictions, nor was I asked at the two stage interview. I spoke mainly of my current employment and what I did there, at no point did they ask me about convictions so I didn't disclose them. I was offered the job and took it. I gave a weeks notice at my kitchen job and started in August 2017 and I am still currently working there to this day. The pay isn't brilliant (minimum wage+overtime opportunities) but at least it's steady money.
I hope you find something, best thing to do is to try and get any job no matter how much you dislike it, just get on the ladder. Kitchen work is a good stepping stone. Not all employers ask about convictions as I found out. Keep trying I'm sure something will come around. You will gain more knowledge of what is required the more interviews you attend, they aren't all the same. Some are more in-depth than others, just tell them what they want to hear, don't reveal more than is necessary.