Whilst having one program or one book may seem easier to manage I think the best idea would be to expose yourself to a variety of resources so that you’re not limited to relying on one particular website or one particular textbook. Edrolo I think should be one of your main go to resources as it’s tailored for the NSW syllabuses for Stage 6 in a handful of subjects. My next suggestion is Khan Academy as although it’s been americanised for their syllabus in AP subjects or whatever they have there, it’s still a very good website and has helped me out greatly in the past. My last suggestion would just be YouTube - I find some people often don’t use YouTube that much for videos which is a shame because there’s so many good people on YouTube which you could watch to get help. For sciences on YT I’ve watched ‘Bozeman Science’ or something like that, he’s super good! Even for humanities subjects I’m sure there’s a variety of videos you could use for help. Lastly if all does not work, ask around for help, whether that would be with teachers or friends.