I know you are not 打手 and I understand how frustrating this can be for you.
Yeah, unfortunately 83 is an end of line product, so there probably won't be many updates from now on. Sorry to hear about the TrueHD issue, though. Hopefully, they can fix it.
However, reading through online forums, you will find problems with Sony/Pioneer players as well. I think this is just the nature of Blu-ray technology. There simply is no perfect player at this point. So BEWARE many BD players can have their issues as well.
Nonetheless, in terms of firmware support, OPPO is still one of the best in terms of addressing known issues.
As for playing DVDs in 24p, unfortunately, this is not a priority to manufacturers as the number of people that pay attention to this is very small. Personally, I am not really that concerned as I believe there are very few natively encoded 24p DVDs anyway. I'd just set source direct and forget about it.