Last year the Rams were #5 (52.76%) behind the #1 Packers. This year they are #29 (46.7%).
In their last 3 games where they lost, the Rams are only 40.91% ToP. Against the packers it was 33.89%.
https://www.teamrankings.com/nfl/stat/time-of-possession-pct-net-of-ot#:~:text=NFL%20Team%20Time%20of%20Possession%20Percentage%20(Excluding%20OT),%20%2040.19%%20%2028%20more%20rows%20Time of Possession is a good indicator of how good your offense is at keeping the ball, though huge home run TDs can reduce that. It’s also a good indicator of how good your defense is at getting off the field.
Everyone hated the dink and dunk 12 play drives by Goff last year but the offense held the ball and the defense had a #1 overall rating. This year the offense is more boom/bust with Stafford resulting in quick TDs or Turnovers. Include McVay's abandoning the run and that too will decrease your ToP.
I think the drastic change in ToP is both on the offense and defense... It's a huge swing right now from last year to this year...