I did an advanced PPL course once, but they called it a CPL.
Strikes me that if you're unhappy about any aspect of your skill, just fly with a suitably experienced and qualified instructor and ask them to provide you with some remedial instruction.
If you just want to up your flying standards, pick something that's new and do that - floatplane, tailwheel, instructor, aerobatics - the list of stuff available is pretty much endless (or at least, most of us will never afford to go down everything that's on the list). For me, most recently that was an aerobatic refresher having not spun an aeroplane for three years - did me a world of good and I really must go back and do some more.
G