If you were blessed to miss the first 15 games of the 49ers’ 2024 season, San Francisco gave you a Cliff Notes version of it Sunday in Miami.

The 29-17 loss to the Dolphins perfectly encapsulated the campaign: statistically strong but fundamentally rotten.

On Sunday, the Niners averaged more yards per play than the Dolphins. San Francisco’s defense held Miami to 4-of-12 on third downs and only one red-zone touchdown in three tries.

Check a spreadsheet, and the Niners did well.It’s too bad football isn’t played on a spreadsheet.

On the actual grass, in a game played by well-compensated men, the Niners were a disaster. Sunday’s game brought another string of injuries and some of the worst situational football you’ll ever see on both sides of the ball, resulting in a loss.

Yes, Sunday’s performance was the same kind of game that was explained away early in the season, bemoaned in the fall and has become unavoidable in the twilight of the campaign.

The Niners had 11 penalties for 90 critical yards, doubling up a not-exactly-buttoned-up Dolphins squad in that category. They couldn’t run the ball, which was supposed to be head coach and offensive coordinator Kyle Shanahan’s whole “thing.” They converted only 5-of-14 third and fourth-down situations, and Brock Purdy, playing behind a backup offensive line, threw a game-sealing interception with two minutes to play.

I’m getting second-hand embarrassment just typing this stuff.

“No matter what’s going on, when you have those penalties like that, you don’t deserve the win. The offense — the biggest thing was lack of concentration,” Shanahan said. “(And) you can’t have three personal fouls on three drives (on defense) in the second half and expect to win.”

And the Niners have not won. It’s hard, after all, to play two opponents every week: the team on the other side of the field and yourself.

That said, I heard many suggest going into Sunday’s Week 16 game that with the Niners playing unburdened games — San Francisco had no chance to make the playoffs before kickoff — they might play their best football. The pressure of a Super Bowl-or-bust season had been lifted; might the team’s play lift, too?

Oh, to be so naive. This kind of stink doesn’t simply wash out.

Indeed, we saw a contest in perfect South Florida conditions that suggested that the Niners cannot help themselves from self-destructive behavior.

In fact, it suggested that these Niners haven’t underperformed all season — they might have overperformed going into Sunday’s game.

The Dolphins entered Sunday’s game in a bad spot. They needed all the help they could get to win and stay in the playoff race. The 49ers provided that kind of help and more.

On the second offensive drive of the game, the Niners stacked a hold, false start and sack, turning a nice bit of early-series momentum into a third-and-23 failure and a punt. Great start, gang!

San Francisco was just getting started.

The Niners followed that with a false start on a second-quarter third down to take a bad situation and make it impossible.

Then the Niners took three points to end the third quarter despite being on the Miami 3-yard line in a six-point game without material meaning in the standings. That was lame.

The all-around failures kept coming in the second half, too.

The Niners spotted the Dolphins 15 yards with an unnecessary roughness penalty on the first play of the half.

Then rookie Ricky Pearsall was flagged twice for illegally lining up to first knock the 49ers out of the red zone and then to wipe out a big third-and-long conversion that took the 49ers to the Miami 2-yard line.

Of course, the Niners missed the field goal at the end of that drive. What else did you expect?

And down 19-17 in the fourth quarter, the Niners had two more unnecessary roughness penalties, the latter of which was followed by an offside penalty, giving arguably the NFL’s best kicker 20 free yards of field position. Unlike the Niners’ kicker, Jake Moody, Dolphins kicker Jason Sanders made his non-chip kicks on Sunday.

Then the Niners, trailing by five with 2:10 to play, could only muster one play before Purdy, who spent much of this game running for his life — and that’s barely an exaggeration — threw an interception without a 49ers receiver in the vicinity.

Oh, and the Niners also had two more special teams penalties, too. That’s now four in the last two games.

“It’s happened way too many times this year,” Nick Bosa said. “It’s very frustrating all around — offense, defense, special teams. When you have that many penalties, that’s kind of a harbinger of a loss.”

“It’s just bad football, and I don’t put that on Coach Shanahan, I don’t put that on our wide receivers coach and line coach, tight ends coach, that’s on us,” said George Kittle, who caught eight passes for 108 yards and was one of the Niners’ few bright spots. “We know what the formations are, we have to go out there and execute. I messed up one.”

Folks, I hope I’m not the first to tell you this, but this is a bad football team. The 49ers’ rise to excellence — four NFC Championship Games in five years — was rapid. The Niners reached the Super Bowl in Year Three of the Shanahan regime.

The decline might prove to be even faster.

Sunday’s loss moved the Niners to 6-9 in the 17-game season. At this point, they’d be better off losing the final two games for draft position. The good news is that it seems like a likely output regardless of whether or not the Niners tank the final two games.

But while 2024 being a lost and losing season for the 49ers is certain, what remains unclear is how much they need to do to right the ship whenever it mercifully ends in two weeks.

Maybe Deebo Samuel, who had a renaissance game Sunday, totaling 121 yards and a touchdown, joined Shanahan, Purdy, Kittle, Bosa, Fred Warner and the Niners’ rookie-deal players as the foundation for 2025 and beyond.

Maybe not.

For Samuel and so many other Niners — both on the field and in the coaching ranks — two weeks remain to save their jobs.

Because after Sunday’s disastrous and encapsulating performance, you can easily argue that everything that’s not bolted down should go.