If the application is not online in China, you can't download it.
You can only reapply for an Apple account. To apply for this account, you need to publish the support area for the application. You can download it by logging in to the AppStore with this new account.
In addition, Onion Browser is a small open source iOS Web browser, which can be used for Web browsing through Tor network.
Generally speaking, some software is not easy to download, especially when it is limited, then you can also search in the browser that comes with your mobile phone, and you may find download channels or download resources.
I hope my answer is helpful to you. Welcome to adopt it. Thank you.