When I trigger a search for your first example, I do immediately get a result from the first source (using the default settings): https://i.imgur.com/WfP6oaZ.png

If you don't see any results, then access to the sources may be blocked (e.g. by the network adminstrator). Follow up by mail and provide more information if you want help.

The project is currently in maintenance-only mode because it is basically finished and I have other priorities (most of the updates are about modifying the set of supported sources).

There is no officially supported way to import/export via a config file, but you could use the developer tools of the browser to directly read / modify the preferences.

To debug an extension, see the guide at https://developer.mozilla.org/en-US/Add-ons/WebExtensions/Debugging

After opening a debugger for the extension's background page via about:debugging (see the above link), you can interact with the storage via the chrome.storage.local API, as documented at https://developer.mozilla.org/en-US/Add-ons/WebExtensions/API/storage/local

For example, to convert the storage to something that you can copy and paste in a file, run the following from the debugger's console:
chrome.storage.local.get(null, items => {
console.log( JSON.stringify(items, null, 4) );
});

You can then manually edit the configuration in the file (at your own risk), and save the changes back as follows:

chrome.storage.local.set();

For example:

chrome.storage.local.set({
"panelOffsets.youtube": {
"top": 100,
"right": 204,
"width": 275,
"maxHeight": 600
}
});