ThirdParty lib issue at runtime on Linux

Hello, everyone,

at the moment i’m using Unreal 4.24.3 under Linux and i have a problem when i start the Unreal Editor with my project.
The ThirdParty Library is integrated via a plugin. The ThirdParty Lib is available as static (.a) and dynamic (.so) file.

Problem 1: I link against the .a lib => I get the error message that I should activate -fPIC.
Can I enable this in the build.cs? - Recompiling the engine should also be possible.
What disadvantages would this option have (significant performance losses should not occur).

Problem 2: I am linking against the .so lib => Compiling and linking works and when starting the Unreal Editor stops at 73% with an error that my Unreal Plugin cannot be loaded.
messages:

LogCore: Warning: dlopen failed: (null) 
LogModuleManager: Warning: ModuleManager: Unable to load module ...

Unfortunately these messages are not very verbose. Can I get more debugging information?

Greetings,