Epsilon-and-mu-near-zero (EMNZ) metamaterials have garnered significant attention in near-zero-parameter metamaterial research for their exceptional ability to attain concurrent near-zero permittivity and permeability. Nowadays achieving EMNZ properties through the use of metacomposites remains a novel endeavor. Presented here is an innovative approach of near-zero-parameter metacomposites, illustrating excellent and tunable EMNZ properties in the radio frequency regime. The self-organization approach is applied to construct the conductive 3D network and the circuits, serving as the underlying framework for achieving EMNZ properties. Near-zero permeability is effectively maintained while permittivity reaches epsilon-near-zero frequency regime. Efficient manipulation of electromagnetic parameters is initially realized via adjusting component content in metacomposites. Significantly, an excellent EMNZ property is observed as carbon content reaches 15 wt.% at 915 MHz. Through both numerical simulations and experimental testing, the PGC metacomposites have exhibited tunneling effects and directional emission characteristics, confirming their EMNZ properties. Besides, the Lego-like adjustment facilitates the achievement of EMNZ property and advances the EMNZ frequency point to 700 MHz, expanding the EMNZ range. Furthermore, thanks to the remarkable excitation effect of photo-induced adjustment, the metacomposite with low-carbon content also achieves extraordinary EMNZ properties. This research offers promising self-organized EMNZ metacomposites and lays the foundation for future endeavors in precisely adjusting near-zero parameters.