I had two OP babies and nothing helped to turn them and believe me I really tried when I learnt DD2 was presenting (consistently) OP at 35ish weeks. I think it's just one of those things, they'll turn if they want and won't if they don't want to. I saw an amazing acupuncturist with DD2 and he honestly felt it was luck of the draw despite practicing turning techniques frequently on his patients.

DD1 was a relatively quick labour for a posterior baby, 6 hours established (8 on my watch) but an hour of pushing with no head on view. She was a vacuum delivery in the end.

DD2 was fast and furious - 37 minutes (47 by my watch though) and turned as she exited. No intervention required. The back pain was no where near as bad as with DD1 either but maybe the speed at which she arrived kinda numbed that IYKWIM.

Good luck and try not to worry. I was pleasantly surprised with my second OP birth, it was just a little too quick!