I'm on macOS Sonoma 14.5 and I updated Xcode to version 14.4; the steps that worked for me are:

1. Open Finder.

2. Goto the below directory /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/; You can also click command+shift+G, copy-paste the above directory, press return and this should take you to the directory.

3. Create a new folder in the directory. Rename it with bits.

4. Now, open Xcode, click on File in the above menubar, select >new >file, click on macOS, select header file and create one named stdc++ and place it in your desired folder.

5. Click here; this includes all the necessary header files, copy-paste all the contents to the stdc++ header file and save it.

6. Now, copy the header file and goto the directory in step 2, open bits folder and paste the header file there.

7. Exit any running IDE (i.e. VS Code).

That's it! You're all set. Now, open your desired IDE and Voilà! You can now include bits/stdc++.h in your c++ file. Hope this helped. :-)