JButton sizing in Panel?

[turbid ravine]

I've attempted 3-5 different means of putting buttons/components into this JPanel, but I have so far failed to find how to resize the individual entries because the panel sizes them itself.
I feel as though I have some fundamental misunderstanding of the Panel; I'll attach an example.

Here is where I struggle:

private JPanel makeButtonsPanel() {
    JPanel panel = new JPanel();
    panel.setLayout(new GridLayout(7, 0));

    JButton settings = new JButton("Settings");
    settings.setPreferredSize(new Dimension(100, 50)); // <---
    panel.add(settings, BorderLayout.CENTER);

    return panel;
}

    public ThisPage() {
        JFrame landing_frame = new JFrame();
        landing_frame.setPreferredSize( new Dimension(1920, 1080) ); //temporary sizes

        JPanel landing_panel = new JPanel();
        landing_panel.setLayout(new GridLayout(0, 3));

        landing_panel.add( makeButtonsPanel(), 0.0f ); // <---

        landing_frame.add(landing_panel, BorderLayout.CENTER);
        landing_frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        landing_frame.setTitle("PLO");

        landing_frame.pack();
        landing_frame.setVisible(true);
    }

It may be that JPanel is the wrong tool for having customized sizes for items, maybe I'm just using the wrong LayoutManager for this?
I did see the post "JButton Sizing Not Working," but I've attempted both solutions presented there (but may have done at least one wrong).
This is my first experience with JFrames; any help would be appreciated.

[smoky cobalt]

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[brittle geyser]

You're supposed not to care so much about item sizes and instead let the computer size them according to your chosen layout

In practice you'll just configure the layout managers to size themselves rather than indivudual items, to keep consistent alignments

Generally you won't guess anything. Follow tutorials