Important loss for the Jets, they can't afford to win even a single game, if they want Trevor Lawrence. If the Jets drop out of the top spot, then they will need to embrace Darnold at QB, trade down to accumulate talent (ideally moving down 2-3 times for teams that want QBs like Fields, Lance, etc.) and hope for the best.
I don't feel that the Jaguars have tanked, they just have had some hard-fought games, brutal luck, some injuries and horrific QB play. The Jags have some young and talented players in Chark, Shenault, Conley, Collin Johnson, Robinson, Norwell, Cann, Shatley and Taylor on offense. With some pieces also on defense in Sidney Jones (who needs to stay healthy), C.J. Henderson, Myles Jack, Costin, Josh Allen, etc.
For the Jets though, it will be more than just "winning" that top spot. They also need to bring in a quality head coach and might even need to think about a team president who commands respect, if they opt to keep Douglas as GM. The Jets biggest job might be selling Trevor Lawrence on the idea that the Jets are on the right path.
While the allure of the NFL and a big payday will probably get Lawrence to come out, you can also tell that the kid loves playing at Clemson, so he has some leverage by threatening to take out a big insurance policy and return to school. The Jets will need to show Trevor and his advisory team that they can build and field a winner.