Enh. I've been watching a lot of US court proceedings on YouTube over the past year or so. Turns out a lot of things I took for granted about our justice system are either Hollywood nonsense, or urban legends, or both.
Plea deals in the US are more about expediency and pragmatic leniency than anything else. Police bodycams are a big factor, I think. People who are caught dead to rights by the evidence get offered probation instead of prison time because the prisons are overcrowded, the court docket is backlogged, and nobody wants to drag thirty citizens away from their lives to make up a jury pool.
And, in stark contrast to the UKian system, if someone does want to take their chance with the evidence, and they lose anyway, the fact that they opted to go to trial is not held against them at sentencing time. Think of the US plea deal system as a form of non-binding arbitration. The two parties get together, discuss the various factors of the case, and see if they can reach an agreement. That's then recommended to the judge, who either accepts it or not. Meanwhile, in the UK, the court just holds a grudge against anyone who goes to trial instead of confessing at the outset.