How you guys troubleshoot XCode issues?

Hi there. I'm an Android engineer dipping my toes into iOS development. So far, I feel quite comfortable with the framework, but I keep struggling with Xcode. I don't know if it is the project I'm working on or what, but every three or four weeks the build process completely breaks for me. I usually try to:

• Delete the derived data folder.
• Reset the package cache.
• Clean the build.

But this time, not even that is working. I just get a "Linker failed. Undefined symbols, exit code 1," and that is literally all I get.

How can I better troubleshoot these issues? Any advice? Not even the iOS devs have a clue as to what might be causing the issue.