Take a little time to reflect on why you decided to learn to play the piano.
I'd put a sizeable bet (maybe even a Kit-Kat) that it wasn't for the sake of getting some exams.
You mention that you want to be able to play most songbooks with confidence. So why not choose a couple of books with music in that you like the look of (or have liked the sound of) and use those as a "benchmark" of what you want to achieve.
Maybe keep a "greatest hits" list with the music you most want to be able to play eventually - and talk through with your teacher how you would go about developing sufficient technical ability to able to play them. You could always update the "greatest hits" if you hear/see something else you'd like a crack at.
Alternatively, why not work on exam requirements and tick them off for yourself, but don't actually go through the exam room process. You'll know you've learnt the necessary stuff, without the hassle of the day itself.
Either way, you need to refocus away from the exams being a destination, they are only features on the landscape while you are on the journey.
Best of luck, and enjoy your playing
Katyjay
(ps, at the moment I only have one work on my "Greatest Hits" list, and I've still got a way to go to manage it even in practice, let alone performing it.....but it's still a long term motivation for me

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