The 49ers don't have a playcalling issue. They have an execution issue.
Week after week, I've evaluated the 49ers' offensive film to understand where the problems stem from, and it's the same answer every week: execution.
In Week 10, the 49ers scored just 22 points, as they converted only two of their five red zone drives into touchdowns, while leaving other points on the board elsewhere.
First Red Zone drive
On 1st & Goal at the LAC 9, Jimmy Garoppolo threw an incompletion out of the endzone to a well-covered Deebo Samuel.
This play was poorly called, as there were only two developing routes, with George Kittle going to help Mike McGlinchey block, while Kyle Juszczyk gets lost in the traffic.
Brandon Aiyuk is well-guarded along the sideline, while a safety helps to cover Deebo Samuel, leaving him in tight double coverage.
On 2nd & Goal, Deebo Samuel takes the carry, but doesn't follow Trent Williams, his lead blocker, instead cutting to the left and getting to the two-yard line. Had Samuel followed Williams, he likely runs into the endzone for a touchdown. That's the first execution error.
On 3rd & Goal, the offensive line can't gain any push at the line of scrimmage, and Christian McCaffrey is swallowed up at the line of scrimmage, forcing a field goal opportunity instead of a go-for-it on 4th & Short.
Second Red Zone drive
The 49ers get to 1st & Goal at the LAC 5-yard line, where Christian McCaffrey pushes forward for a three-yard gain.
Then, on 2nd & Goal from the LAC 2, McCaffrey gets the carry again, inching forward for another yard to set up an opportunity at the 1-yard line.
Jimmy Garoppolo seals the deal with a quarterback sneak on 3rd & Goal, securing the 49ers their first touchdown of the game.
Third Red Zone drive
The 49ers get to 1st & Goal from the LAC 7-yard line to begin this series of plays.
On 1st & Goal, Jake Brendel and Kyle Juszczyk whiff on their respective blocks, allowing Chargers defenders to swallow up Elijah Mitchell for no gain.
On 2nd & Goal, Jimmy Garoppolo incorrectly reads the RPO, throwing the ball to Elijah Mitchell, despite the edge rusher aiming for the passing situation. If Garoppolo hands the ball off to Deebo Samuel, it's likely a touchdown. Instead, San Francisco loses a yard on the play.
On 3rd & Goal, Brandon Aiyuk drops a pass from Jimmy Garoppolo after running a good route, as the ball hits off his hands and falls incomplete. Either this play or the previous play could've resulted in 49ers' touchdowns, but instead force the team to settle for a field goal.
Fourth Red Zone drive
On 3rd & 10 from the LAC 26, Jimmy Garoppolo delivered to Brandon Aiyuk, who gets ten yards after the catch to end at the LAC 2-yard line.
Christian McCaffrey quickly finished the drive with a 2-yard touchdown run on 1st & Goal from the 2-yard line, which gave San Francisco a 19-16 lead at the time.
Fifth Red Zone drive
San Francisco's fifth red zone drive had a chance to put away the game for good as they started on the 8-yard line after the Chargers turned the ball over on downs.
Up 19-16 at the time, a touchdown would've made the game a two-score bout with a minute remaining, sealing the game for the 49ers, but they were unable to execute.
Elijah Mitchell had a strong first down carry, gaining six and setting up a 2nd & Goal situation at the LAC 2-yard line.
On 2nd & Goal, Spencer Burford was unable to get to the second level on his linebacker Kyle Van Noy in time, who sprung into the hole and made the tackle on Elijah Mitchell a yard short of the goal line.
On 3rd & Goal, the 49ers faced two execution errors that killed the opportunity to score a touchdown. First, Mike McGlinchey whiffed on his block on the right side. Second, Elijah Mitchell slipped and took an extra step on the outside before cutting inside. Had Mitchell not taken that extra step, he would've been able to cut and reach the endzone, even with McGlinchey's error.
Regardless, the play failed as a result of the execution errors and the 49ers kicked a field goal at the 1-yard line. Ultimately, the game ended one play later when Justin Herbert's pass was altered by Charles Omenihu and ended in the hands of Talanoa Hufanga, sealing the deal for San Francisco.