First off - I’d highlight the value of redefining what some state as “negative” beliefs, with the usual preconceptions of “negative = bad...”
That dualistic outlook with its inherent judgementality is perhaps one of the biggest to transcend, a transition which opens up immense possibilities.
Everything has its time, place, and value. Even beliefs that may seem “negative” have some role to play - thus, there may be more to gained in acknowledging those aspects rather than dismissing as “bad” right away...
As for specific techniques, etc... there are so many different modalities and teachers - again, each with the own value, which serve a time and place...
The “best” would be not a one-size-fits-all answer, but depends on what works best for a particular individual, at the particular point they’re at, dependent upon the conditions & dynamics they’re in at a specific point in their own growth process.*
I went through alot of personal development teaching various types of techniques you’re asking about - and each was a certain step on the journey, not particularly any better or worse than any other. At this point, I might be able to say that taking that approach of unlearning specific beliefs might be a very slow, ineffective approach altogether - working at the micro level when much more can be unravelled and reprogrammed working at higher macro levels. Yet, it may not be the most helpful to provide direction to what would work best for me, as if you - or anyone else reading - doesn’t have the foundation laid with experience in the other micro-aspects, it might end up being counterproductive.
Hence, I’d more likely recommend that each pursue their own course of exploration and intuit their ways to what works best for them at a given time.
(Although when the time arrives that @core opens up public access to the next round of his quantum AI - autonomic intelligence - technology, there may not be reservations in sharing it as something everyone may be able to jump into and benefit from, should they feel inclined to do so... ;-) )