Hi James_20
I apologize for all the trouble it has caused and sorry about your time.
As per your description, the behavior you encountered is by default. If users are the first time to use a new App, then firstly PowerApps would require the user to verify the connection permission used in this App.
I search a lot and here is found related thread according to your error message please refer to this thread and see if help.
Users receive an "Almost there [app name] needs your permission to use SharePoint
Also, you can set it so that prompt is auto accepted, and the user is not prompted using PowerShell. Here's a BLOG post that will walk you through the steps.
https://www.o365dude.com/2019/01/06/bypass-consent-pop-ups-in-powerapps/
Disclaimer: Microsoft provides no assurances and/or warranties, implied or otherwise, and is not responsible for the information you receive from the third-party linked sites or any support related to technology.
I appreciate your patience and understanding.
Best Regards
Waqas Muhammad