I don't see her winning that many more, maybe a couple more. She's great at mopping up the wins when the big names fail, but she needs to be able to beat other top 10 players in slams if she is going to win more of them. I also think in a couple of years players like Anisimova will be rising to slam winning level and this will draw a curtain down on her slam winning period. It also depends how she copes with the attention and pressure of being a slam champion and top two seed in the next two slams - she has yet to reach the qf in either of them - and of course, how she copes with the pressure at home in Australia at the AO.
I'd be very surprised if this is her only slam, but I doubt she'll get above five.
She's going to be a contender at Wimbledon, which has a smaller list of potential champions than the hardcourt majors or the French, for a long time with her game, and while it's hard to see her winning the French again, certainly the way the Australian has played the last few years should give her some opportunities to win there.