In my experience, AAC is always codec with best connection. For that reason you see so many truly wireless IEMs using AAC. Can you tell me what source/phone are you using when facing these problems with SBC? Shutting down on fully charge is change software team made to both M0 and M5s. They didn't really looked into all user scenarios, so we will need to adjust it a little bit to be more practical. Will see if I can make some playlist with similar thing to test it out. Unfortunately this is not about script, but about using different BT profile. No plans to add it now, since it could be causing some other problems.