Hey ct! I'd say it's better to use a formula column instead of a merge column, that way you can use the AI to generate the specific result you're looking for.However, you can add a space to Merge columns but it does involve writing it in the formula.
Took a quick peek at your table and it looks like you have the column properly set up with formulas, the only thing or issue found was that the first name column was deleted? it's showing an error that the input source is missing