You're missing most of the equation. Just looking at their averages isn't how it works.
Lakers averaged 26.6 fta/game, best in the league. They only gave up 20.8 fta/game, also best in the league. So against the AVERAGE team, their gap was already 6 free throws. And after AD/Reeves returned and the Lakers picked up all those players in trades, the gap from February-April was actually over 9 free throws.
Warriors averaged 20.2 fta/game, worst in the league. They also gave up 25.2 fta/game, sixth worst in the league. So against the AVERAGE team, their gap was already -5.
If drawing fouls was simple addition, and the new Lakers were 9 better than the average team while the Warriors were 5 worse, then you would guess that the new gap should be 14. But in reality, free throw disparity is more than simple addition. Because the Lakers know how bad the Warriors are at defending without fouling, they attack even more than usual. Because the Warriors struggle to score inside against the Lakers, they draw contact even less than usual. As a result, the free throw gap doesn't just add, it increases even more than that.
The expected free throw gap should be something larger than 14. In reality, the gap each game (not counting intentional fouls at the end) has been:
21
1
20
6
0
Honestly, the 21 and 20 are slightly high but not unexpected considering how different these teams were in the regular season. The 6 is very low, but not impossible as a one-time event. The 1 and 0 are absolutely bizarre. How does by FAR the worst free-throw drawing team in the league, going against the BEST free throw preventing defense, manage to get to the line just as many times as the BEST free throw drawing team going against one of the worst free throw preventing defenses? And not just once, but twice in the same series....both times in must-win games that otherwise would have meant an early end to the series?
Anyone who is serious about it would see Games 2 and 5 as dramatically different from the norm that had been established in these team's play all season.