He left, so their wealth is not his to spend, but he wouldn’t be in a privileged position to start with without them. Not sure why the Guardian is calling him Prince still though, unless it’s just for reader recognition, rather than just some Harry bloke.

https://en.wikipedia.org/wiki/Finances_of_the_British_royal_family#Assets_held_in_trust_by_the_Sovereign

https://www.investopedia.com/ahead-of-king-charles-coronation-here-is-the-british-royal-family-s-net-worth-7486580

https://www.bbc.co.uk/news/explainers-57559653

I’ve never dug into it but these are the first couple of links for Harry personally

https://parade.com/culture/prince-harry-net-worth

https://www.businessinsider.com/prince-harry-meghan-markle-net-worth-spending

NFI of the accuracy of any of that