I guess that depends on who you ask. That tends to be the case with sexual anything though.
For me personally, the best orgasms I have ever had have been hands free prostate orgasms. But I think part of that is the head space that I'm in at the time. I have played with toys and also have a few BD toys. But I have never been able to reach the P-spot O on my own. I've heard that not cumming for a week or so makes it easier, but it never did for me. When I'm playing by myself, I'm to focused on achieving orgasm, which, coincidentally, I have a suspicion is the same problem you are having. I have found that the P spot orgasm happens for me when I'm not trying to have one. I'm just relaxed and enjoying being penetrated. I believe that is the key. Remember that it's not about attaining orgasm, it's about enjoying spending time with yourself. You need to be relaxed, enjoying yourself, and reveling in the pleasure of the experience. For me, the only way I can do that is when I'm with a partner. Otherwise I get focused on using the toy and then my arm or legs get tired or I'm in a weird position or whatever. Forget about the end goal being an orgasm and shift your mentality to just trying to give yourself the most pleasure for as long as possible.
Also, do some research into male anatomy. Perhaps look into medical school books on proctology. My guess would be that there is a section on locating the prostate in order to do an exam; the prostate my not be where you think it is and you may actually be pressing on your bladder.
But also keep in mind that everyone is different. Just ask any woman about their discoveries into their own sexuality. Some can cum from clitoral stimulation alone, some can't. Some women can cum from penetration, some can't. Hell, I've been with a woman who could cum from nipple play alone. Men are similar. we all feel pleasure in different ways. Some men get hard while being penetrated, some instantly go soft. Some can reach a P-spot orgasm with very little effort and some men, no matter how much they try, will never be able to achieve one. That's why my advice would be to change your goal. Being intimate, with yourself or a partner, should not be solely focused on reaching orgasm. But rather enjoying the experience as much as possible and being okay with not having an orgasm sometimes. The important part is that you are enjoying yourself and gaining pleasure from your playtime and if you happen to orgasm even better.