I wouldn't go as far as calling it "mostly meaningless"

Well, to start off goals and assists only even begin to measure one type of player - attackers. They do not represent the impact someone like Rodri or Toni Kroos has.

Even then, goals scored and assists created have proved a poor statistic in terms of predictive power - hence why so called "advanced statistics" began being developed. Expected Goals (or xG) was an early development attempting to measure the quality of chances created, for example. The field is much more advanced at this point however, with xG expanded into concepts like Expected Threat as early as 2018^[1] and Possession Value models ^[2]

From a recruiting perspective for instance, I would assume that it would be interesting to devise a statistic to indicate how much a player improves the team they're on, while somehow factoring out the effects of the other players.

Attempts to translate statistics such as "X Above Replacement" has been made, see this article by Dan Altman for instance ^[3]