Again, no offence meant, but it is entry level, albeit at the top of that range. Anything with a '4' is the minimum standard for my keyboard students taking exams and once they reach Grade 3, they'll have to upgrade, to a '7' or preferably '9' (and that would the last upgrade they'd need, even going up to Diploma level.
You are asking it to do more than it was meant to do and, to be honest, it's doing a lot more than that level of Yamaha keyboard used to do. I can remember being able to load in just 5 basic styles and then to choose just one of them to be available at any one time. And the only way to load them into the keyboard was with a old and slightly flaky piece of software called Musicsoft Downloader.
I'd always encourage you to push the keyboard to its limits, but equally to realise when you do reach them. Maybe at some point you'll upgrade, but look around for a good used instrument. I sold my last PSR-S900 for just £500 when I upgraded to a PSR-S970.