Obviously AH lied about JD, but given how her lawyers have actually good reputations and are shown to be competent individuals, apart of me wonders how they could've seriously have allowed her case to completely devolve like this where it's very very likely she is going to lose against JD.

I believe more than likely she told the lawyers only her version of the events and possibly lied about much of the authenticity of the evidence (probably didn't mentioned she edited pictures or anything) and testimony (probably didn't mention there were other more credible witnesses who counter AH's witnesses stories) she had for her case. Like, I also think AH didn't tell them she fully intended to make the case about smearing JD and that she would be claiming a bunch of stuff she wrote about him in the Op'ed as being about him.

I am not a lawyer but if I was one, I would've told AH to simply make the entire defense around how the Op'ed doesn't name JD in any way making it impossible for JD to win or provide more evidence counter to her claims. This would've made it impossible for JD to win the case and simultaneously would've made it impossible for JD to bring up evidence that would've revealed AH as lying since much of the evidence and witnesses JD brought forth was only possible because they were rebuttals to AH and her witnesses claims about JD. If AH simply didn't have any witnesses and simply sat there and denied the entire time that the Op'ed was about JD and said nothing more she could've won the entire case because again the entire case centers around the Op'ed and how it defamed JD.

I believe due to either incompetence or arrogance or both, that AH basically has sabotaged her entire case and undone so much of the work her lawyers have been trying to do which inevitably resulted in her lawyers coming off as foolish simply by proxy. Basically, we owe it to Amber Heard for essentially providing everything Johnny Depp needed to not only likely winning this case, but also essentially proving JD's innocents and AH's guilt.