I think in reality, if there was pervasive anarchy for everyone without any overarching state, there would be more opportunities and incentives for deal-making between gangs and violence would trend towards zero.
Currently, it's illegal to make deals with gangs and they're almost 100% made up of people with criminal tendencies since honest people don't want to be associated with gangs. If every social group was a gang and there was no state, then people would have a strong incentive to join a gang for protection/support and so there would be a lot of good, honest people inside those gangs and this composition would make the gangs less violent.
I guess with this terminology, it sounds a lot more appealing than 'gangs' so I'm fully in favor.
2. But more importantly, most anarchists are not just against hierarchies. They are positively for society or the group to have features likes mutual aid, worker rights, democratic or consensus based decision making, etc. All of these are missing from cartels.
Drug cartels are not run along anarchist lines.
I think you have a misunderstanding of the basic concepts here.