A label is not one thing. The sticker on an item, the 4x6 on the box and the slip inside it are three different documents at three different sizes doing three different jobs. Each one can be claimed by a different printer, and the one you will touch most is built to be rearranged without anybody writing a template.
The item label is not a fixed layout at a fixed size. It is composed to the physical page you claimed, so the same template prints correctly on a 1x1 sticker and on a 3x1, with the barcode scaled to the height it actually has rather than overflowing or floating in white space. You do not maintain a template per roll.
Every standard design is there to browse and filter, and to preview at the exact size it will come out, rendered by the same pipeline that does the printing rather than by a mock-up that flatters it. Send a test print from the preview and hold the result. Take a copy of any design into your own account, make that copy the one that prints for its kind, and delete it again if you change your mind.
Item labels for the things you sell, packing slips for what goes in the box, and the carrier shipping label itself. Each is a separate kind, so each can be claimed by a different printer on a different machine.
From 1x1 inch up to 4x6, including the awkward ones: 1.125 by 3.5, 2.25 by 1.25, 1.75 by 0.875. Sizes are keyed in inches because that is how roll stock is sold, and converted for the renderer so you never do that arithmetic.
Shipping labels on 4x6 and item labels on 2x1 is the normal setup, not a compromise you have to make. Each kind of label carries its own claimed size, and a single job can still override it when one automation needs a different roll.
Item labels and packing slips carry a Code 128 barcode drawn as real vector artwork, not faked with a barcode font, so it survives being printed small on a thermal printer. The item barcode encodes the listing, so scanning it later finds the item.
Reorder the rows, resize them across three steps, change their alignment, and hide the ones you do not want. The title and the barcode can be moved and resized but never removed, because a label without either is not a label.
Add a logo and a caption of your own to the item label. Each addition takes its own row rather than floating over the layout, so a logo can never end up printed across the title. On labels too small to carry them, the options are withheld rather than offered and then ruined.
Your changes are stored as an overlay on the standard label rather than as a private copy of it. When the standard label improves, you get the improvement and keep your arrangement. Nobody has to re-import anything.
Which fields print is applied centrally when the job is created, not by whichever client happens to fire it. An extension somebody has not updated for a month cannot print a field you switched off.