Hyundai seem to have a good reputation for support in Australia.
I had zero issues getting the faulty multimedia unit replaced in my Kia under warranty either. They checked it out, confirmed the fault. Ordered the part and called me when it was in so I could make a booking. I was dreading the replacement being done at the dealership (I was expecting the dash to rattle and squeak forevermore), but even that was without issue.
They have tried to tack on some bullshit upsells during servicing though. First service they told me the IAC was blocked with carbon ("Oh really? Send me a picture." It had the usual minor carbon gunge and I told them I'd clean it myself, but realistically have never looked at it in the 7+ years I've owned it since and it still runs fine), and the "left hand rear door check strap has seized and needs replacing" (more like I hardly ever use the rear doors and the check straps are still stiff because they've never worn in, also unchanged and operating without issues for ~6 months).
I have absolutely zero loyalty to any brand, but would buy another given the excellent ownership experience. Even the handful of friends and family I know that own Kias have had no dramas. I did find interactions with the Kia dealers I've come across were easy too (even the salesman wasn't a sleaze!), but had no interest in the local Hyundai dealers where I lived in Melbourne as they seemed to be auditioning for the role of dismissive, know-nothing "the cars sell themselves"/"nothing's available for test-drive right now"/"No, I know the brochure shows 6 different trim levels but we only have the top of the line spec in an auto available in one colour on order - e.t.a 7 months" a la Toyota dealers...