Just enter something like ‘A B C’ into the template. Then create replacements to replace A with Column1, B with Column2, and C with Column2.
https://docs.glideapps.com/all/reference/data-editor/computed-columns/template-column
Then create a Joined List column that points to the template column. Set the delimiter bro something like <br> for your line break.
Finally use that Joined List column as the source of a rich text component.