Solo specific track that is not selected

Try this @Tristan.

The "Solo/Cue" button's role is a checkbox, so you can use the checkboxSet method to explicitly set its state.

function setTrackSoloCueState({ trackName, soloState }) {
    const abletonLive = sf.ui.abletonLive;
    const mainWindow = abletonLive.mainWindow

    mainWindow.invalidate();

    const arrangementGroup = mainWindow.groups.first.groups.whoseTitle.is("Arrangement").first;
    const trackHeaders = arrangementGroup.groups;
    const targetTrack = trackHeaders.getByTitle(trackName);

    const soloQueButton = targetTrack.getFirstWithDescription("Solo/Cue");

    if (!soloQueButton.exists) throw `Could not find the Solo/Que button`;

    soloQueButton.checkboxSet({ targetValue: soloState });
}

setTrackSoloCueState({
    trackName: "TH RUFF",
    soloState: "Enable",
});

Updated as a reusable function

Misread... You are after "Toggle" behavior.

This should work.

function setTrackSoloCueState({ trackName, soloState }) {
    const abletonLive = sf.ui.abletonLive;
    const mainWindow = abletonLive.mainWindow;

    mainWindow.invalidate();

    const arrangementGroup = mainWindow.groups.first.getFirstWithTitle("Arrangement");
    const trackHeaders = arrangementGroup.groups;
    const targetTrack = trackHeaders.getByTitle(trackName);

    if (!targetTrack.exists) throw `Could not find track named "${trackName}"`;

    const soloQueButton = targetTrack.getFirstWithDescription("Solo/Cue");

    if (!soloQueButton.exists) throw `Could not find the Solo/Que button`;

    soloQueButton.checkboxSet({ targetValue: soloState });
}

setTrackSoloCueState({
    trackName: "TH RUFF",
    soloState: "Toggle",
});