This is one site out of a few I've seen that say you don't need a gap. Maybe it's brand dependent, I hope so as we are hoping to use it without a gap.
https://www.bricoflor.co.uk/flooring/vinyl/loose-lay.html
Easy Installation, Easy Maintenance, Easy Removal: Loose Lay Vinyl Planks
Loose lay vinyl flooring benefits from the newest and most innovative installation technology, thus allowing you to save time and money when you choose them over other products. To be more specific, Vinyl flooring simply makes use of physics to stay in place even without glue or other adhesives. The back of every vinyl tile is covered with a special material that has a very high coefficient of friction. That way, these tiles effectively get a strong grip on the subfloor underneath, so strong in fact, that you might not even be able to tell the difference between glue-down and loose-lay planks. But the difference becomes notable later if you need to remove or replace individual tiles. While vinyl tiles and planks featuring other installation systems either leave residues behind, from glue or adhesives or require removing an entire row for just one plank, click vinyl, the loose lay variety does neither. While some effort is required to dislodge a tile or plank, it comes out clean and on its own. Moreover, due to their heavier and thicker build, loose-lay vinyl tiles and planks are guaranteed to stay in place and will not be affected by differences in moisture or temperature levels. Thus, you will not have to leave an expansion gap between the flooring and the walls.