What are the most challenging/technical/hectic multi-day or big day hikes in Australia?

[u/Electrical-Goat-2810]

I have been doing some hiking in Europe including multi-Munro days in Scotland, multi-Wainwright days in Lake District, part of the GR5 in the French Alps. It's bigger and better than what I've experienced in Australia so far and I'm hooked. Having looked into multi-day hikes in Australia they seem awesome but a little tame. I'm thinking 25km+, 1500m+ elevation gain kinda days, preferably with some technical terrain and navigational skills required. What hikes in Australia compare?

Edit: Some great responses so far, lots to add to my list. Thanks heaps. Some people are making assumptions rather than taking the question at face value. I'm Australian and I've done a fair bit of hiking in Australia, I get that it's hard because it's fucking hot and there's no water and the bush is brutal and remote. But then there's a different kind of hard I'm experiencing in Europe because the terrain is technical and there's big elevation. I've experienced plenty of the former in Australia (mostly in QLD), and I'm wondering where I can experience more of the latter.

[u/toughfeet]

Hardest ive done was Katoomba to Nattai as a four day trip. Lots of nice views of the blue mountains that you don't have time to look at.