Update target frameworks to net8.0 for all projects

[MrDoe]

• updated target frameworks to .net 8.0
• fixed error when trying to access inaccessible file (due to permissions)

[pr8x]

Hey, thank you for taking the time to make this PR! Unfortunately, I didn't have the time recently to review it, but I will look at it now.

[stephannn]

Thanks @MrDoe , worked for me