Wait awhile
I see you're completing a scuba qualification. Just because you have a cert card doesn't make you a diver, sounds like a cliche but then the learning begins.
i've been diving 15 years, every time I dive I learn something. So use the skills you've just learned, go enjoy and make the most of them.
A few years down the line if you still fancy flying and can afford to commit to it after the PPL then do it then. I've been flying much less time than diving but every time I fly, I learn something. I've learned far more in the 18 months post PPL than I ever did in taking it.
IMHO no point approaching life the way you might a stamp collection, collecting qualifications for the sake of it then not using them to their fullest.
In answer to the original question 'what do you do post ppl?', for me it was buying a plane similar to the one I trained in and then doing as much flying as possible, visiting as many places as I can. Also got IMC for safety's sake. Aim is hour a week flying absolute minimum.