You aren’t completely wrong but not completely right.
“The issue with general terms and when to use them‘Indigenous’ and ‘Aboriginal’ are broad terms imposed on First Australians without consultation. These are not words they chose for themselves.
While the term ‘Indigenous Australians’ is in common use, many First Australians may not be comfortable with it.
Using ‘Indigenous Australians’ to refer to First Australians is relatively recent. Its use became popular through international discussions, where the term ‘indigenous’ is appropriate (with a lower case ‘i’). But it is a blanket term that homogenises a wide array of peoples and cultures. This can cause offence.
Due to the common use of ‘Indigenous Australians’ in our society, there may be times when you can’t avoid the term. It can come up in discussions with government organisations, in the names of some organisations or in grant applications.
If you must use it, remember to only do so when writing generally about Aboriginal andTorres Strait Islander peoples. The term should always appear as ‘Indigenous Australians’ in the first instance, always with a capital ‘I’. Afterward you can use ‘Indigenous’, capitalised, so long as the context is correct and clear. Using ‘Indigenous’ alone is inaccurate.
Example
‘Indigenous Australians’ is a broad term and covers a large array of peoples. Often Indigenous peoples themselves do not identify using this term, they will use their local community, island or language group.
Indigenous peoples also have regional terms that they use for specific geographical locations, such as ‘palawa’ or ‘Noongar’ to name a couple.
Some people use Aboriginal ‘and/or’ Torres Strait Islander. This is a good idea when the audience isn’t clear or specific. It’s also important to realise that some individuals identify with both groups.”
From style manual.gov.au
Its complex, but basically this is not the place or the audience to use this word and I’m not the person to use it.
I’ve been been taught to avoid using “Indigenous” when talking about people. If First Nations Peoples, or Aboriginal and Torres Strait Islander Peoples, want to refer to themselves as Indigenous (and many don’t) that is how they want to refer to themselves, but many people will not like it and find it offensive.
Using Indigenous you need to know and be sure of your audience. As I’m neither Aboriginal or Torres Straight Islander it may cause offence for me to use the word “Indigenous” but wouldn’t when a First Nations Person uses it.
indigenous is never used with a small i - this is something I see on here commonly, and have seen on this thread.
I always go for the words most preferred by the people themselves.
I have no idea why the Voice to Parliament uses it, but it’s their right to use it, not mine. You’d be better off asking them. Complex.