Using TextMeshPro

To make a billboard glow like a neon sign, you can use TextMesh Pro which presently comes included free with Unity. For instance:

1. With ScoreBoard selected in Hierarchy, create a new TextMesh text element (right-click UI | TextMeshPro - Text).
2. This replaces our standard UI text element, so disable the Text object.
3. On the TMP text, set its Font Asset to Bangers SDF.
4. For its Material Preset, use Bangers SDF Glow.
5. Scroll to Glow settings to adjust the colors and other settings as you desire.

You can even write a script that cyclically modifies the glow settings to make a flashing, glowing sign!

If you choose to try this, be sure to update the GameController's KillTarget script to use the TMP object rather than the UI one. Modify KillTarget.cs as follows:

We may be using the UnityEngine TextMesh Pro classes:

using TMP; 

Replace the data type of the scoreText variable with TMP_Text:

  public TMP_Text scoreText; 

Drag the TMP text item onto the slot in the Inspector. The rest of the script...