Room within a room - noisy neighbours

Hello, I live in a reinforced concrete slabs on the 3rd floor. My apartment is located between the four others: Two sides (left and right) and the top and a bottom. It just so happens that each of the four neighbors behaves very loud: knock, loud conversation, music, etc. I would like if possible to create a small room where I could at least sleep peacefully. It is very important that noise is dominated by the STRUCTURE-BORNE SOUNDS propagating through floor and walls. It is terribly distressing, even more than the sounds of the talks. My first thought, therefore, concerned the floating floor and room within a room. Therefore, over the past few weeks I've read a lot of theories about sound insulation. Despite this, I have very important questions: 1. if building double walls will not make of triple leaf effect? On one side there is a big air space (what about insulation eg, mineral wool on this side ?), on the others small air cavities. How much space between the walls is required before it becomes a triple-leaf system ? 2. does floating floor attenuate structure-borde sound ? I can use rubber, felt, isoplast etc. on many layers. Maybe dense mineral wool could be better ? 3. I'm not a musician who will create music in a room within a room. In view of this, the concrete slab resonance is important in the context of a floating (raised) floor ? 4. Can I treat the original walls, floor and ceiling as the structure-borne sound SOURCE and forget about it, that they are wall ? Then double-leaf wall of my RWAR would create no negative effect (triple leaf). What is more, then I could be working in a large room and my wife sleeping in RWAR would hear less of my keyboard and other sounds (eg, refrigerator) - according to decoupled wall rules in contrast to one leaf wall. 5. External air cavities are not sealed. Is this correct: when sound strikes neighbour wall, this wall is vibrating and produce sound in my large room. Then air compress and strikes outer wall of RWAR. But, as I said, air cavity is not sealed so air (soundwave) should circulate around the RWAR ? I am providing a picture where the red mark it with the noisy neighbors. Of course, above me and below me live loud people, too. Thank you for your help and best regards Plokaji

please update your profile with your location information. the "booth" you are looking to create should help with recording vox and perhaps an acoustic guitar but 1.9m x 2.7m is pretty small...