Thru the first 3 games, the Bills ran on 55.56% of 1st downs.
For the season right now they have run on 48.91% of first downs, which means they have upped their passing quite a bit to move the average that much over the other 8 games.
Over the last 3 games they have run on 43.48% of first downs and against KC specifically they ran on 45.83% of first downs.
So yes, they have become increasingly pass heavy as the year has gone on on first down.
https://www.teamrankings.com/nfl/stat/passing-first-down-pct?date=2024-11-21