I'm having a strange problem with your file, which is forcing me to change my normal workflow. Normally I would group your artwork and select Edit > Cut. But when I do this with your file I get a PDF error, which states that InDesign failed to export the PDF file. As a workaround, choose File > Export > Adobe PDF (Print). Create a PDF and save it somewhere. Next, create a new document that's 400mm x 280mm. Set your margins to 5mm. On the page, create a graphic frame that's 390mm x 270mm to allow for 5mm margins on all four sides. With frame selected, choose File > Place. Select the PDF you made and click to place it in the empty frame. Double click on the Content Grabber (circles in the middle of the image) to select the content (not its frame) and size and position the artwork as you wish. Save your file and choose File > Package to create a package with the original InDesign file, a PDF, and an .idml version as well. All fonts will also be part of the package.
I've done all this for you so you can see what I'm talking about. Here's a download link:
https://www.dropbox.com/s/or4qwmg7o3wapu6/mat_fullsize_ukrainian_2020_sc%20Folder.zip?dl=0
Good luck. I hope this is clear.
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