Across the board and Wall-to-wall

Across the board adverb - Including all.

Wall-to-wall and across the board are semantically related in extensive topic. In some cases you can use "Wall-to-wall" instead an adjective phrase "Across the board", when it comes to topics like inclusive, all-encompassing, wide-ranging.

Wall-to-wall adjective - Present in all places and at all times.

Across the board and wall-to-wall are semantically related in extensive topic. Sometimes you can use "Across the board" instead the phrase "Wall-to-wall" as an adjective or a noun, if it concerns topics such as inclusive.