I currently settled on VSCode with the C/C++ extension. It has good Intellisense and decent enough error squiggles, although these take a few seconds to appear and disappear.
In order to set the project up, just call the Build.sh shell script in your Unreal installation directory:
<Unreal-installation-path>/Engine/Build/BatchFiles/Linux/Build.sh -VSCode <Project-path>
This will generate a code-workspace file with all the build and launch tasks preconfigured.
Pro Tip: Replace -VSCode with -Help to get a list of all the officially supported IDEs and build file formats on Linux