I also share your experience, although I'd guess mine is 100% psychological. It didn't start that way, back as a kind. But I view the process as a self-fulfilling/self-defeating process, which certainly makes sense in my case.
If LC is the only thing that has worked, then do what you have to do. I'd suggest a different outlook on the diets that you found didn't work, but ultimately, just like the question "What is the best exercise?" The best answer is "The one you stick to".
With regard to cardio not helping, I think that's a question of perspective. I used to believe that cardio could be tapped into to a much greater extent than it probably can. Having read Herman Pontzer's 'Burn', a little, I tend to think about things differently. That's not to say that cardio can't be effective, it's just there will come a point (perhaps sooner, rather than later), when the body fights back. It may not be apparent in the workout, at that current moment, but the body has ways of down-cycling that often go unnoticed (reduction of NEPA, NEAT etc.). Ultimately, cardio should be done for all the other benefits it offers, and should definitely be part of the CO side of the equation. But for overall long-term weight success, either leaning more into the CI side, or better still just viewing loss over a much longer period seems to bring many folk more chances at long-term success.
But no, the weight doesn't magically fall off.Nothing magic about any of it
It's often very hard work, especially after the initial bulk drop. But as cliché as it is, it's definitely useful to keep in mind how long it took to accrue the weigh, originally