Instead of using the Horizontal Type tool, use the Vertical Type tool.
Once you’ve added text, in the Character Panel, change the Character Rotation to -90 degrees. This will rotate each character individually.
Next, change the rotation of the actual text object to 90 degrees.
And just like that you have monospaced text in Illustrator!
Use any font you want. Keep in mind that you’ll need to control leading with the tracking control and vice versa. 🙃