Then you’ll have to edit the files with issues. After that you will be able to uninstall it.
The screenshot you posted is a list of hooks. You need to see the files with issues in the PHP8 Scanner something in the ACP -> System -> Support.
I see you already redeemed your keys. You just need to renew it, if it’s expired, download the app and upload it to your board.
https://www.sosinvision.com.br/index.php?/file/43-staff-applications-system/
For Staff Applications System: https://www.sosinvision.com.br/index.php?/announcement/11-ips-marketplace-keys/
There’s no issues in the “uninstall code”. They ARE incompatible as 4.7.15 broke them. It won’t let you uninstall the app due to the changes made. Once uploaded a new version ( a.k.a. Edit the files with missing parameters), you can use or uninstall the app.
You probably have some 3rd-party app/plugin outdated, that’s why it doesn’t work on 8.1.
I would disable all 3rd-party resources and enable PHP 8.1 just to make a test.
In a quick test, it doesn’t seem fixed. As I said last week, nothing changed since Beta 1. All images have same upload time so it doesn’t “respect” the order I set by uploading the files.