across-the-board vs all-encompassing

across-the-board and all-encompassing both are adjectives.

Word	Noun	Adjective	Verb	Adverb
across-the-board	No	Yes	No	No
all-encompassing	No	Yes	No	No

As adjectives, across-the-board and all-encompassing are synonyms defined as:

Other synonyms of across-the-board include all-embracing, all-inclusive, blanket, broad, encompassing, extensive, panoptic, wide.

across-the-board (adjective)	all-encompassing (adjective)
broad in scope or content	broad in scope or content