I think both are equally important.
What I will say though is Lampard's teams have always been good build up sides (until this version we've seen from November onwards of us, I will stress, with that mad 4-3-3 structure that's more like 4-1-2-2-1), and he's then relied more on individual moments from his players in the final third to show their quality, rather than clearly defined moves and patterns of play.
It worked at Derby as he had Mount who was levels above in that league. It worked in his first season at Chelsea to an extent, too, especially when he got Pulisic firing (though he then moved Pulisic to a different position after an injury and it stopped ). It didn't click in his second season there as it was a load of new attackers and frankly they bought too many who played the same kind of roles.
However with this Everton squad you definitely need more clearly defined patterns of play and ways to attack to get to goal - I agree there, and that's on him. On the flip side, if we had some better players, we'd probably also see more quality moments in the final third, wouldn't we. We saw it to an extent at times even last season with Richy.
So IMO we need both.
The stats are grim reading. Over our last 10 league games we've put in 170 crosses. 17 crosses a game isn't bad. Yet only 38 have reached an Everton player, an average of 3.8 per game. That's the standard we're dealing with when it comes to consistency in delivery, and it's the same with passes etc.