You do it in the layout, not in templateDetails.xml:

1. Template style → Layout tab → open the layout the page uses (usually "default").
2. Add a row above the footer section, and in it a column of type Positions. Give it a new name, e.g.

pre-footer

.
3. Save. T4 writes the layout to

templates/<your template>/local/etc/layout/default.json

– so it survives updates like custom.css.
4. In the module, type

pre-footer

into the Position field (it accepts a name that isn't in the list) and assign the menu items.

If the strip should only show on some pages, copy the layout, make a second template style that uses the copy, and assign that style to those menu items.