Very low temperature thermodynamic properties of the YbM₅₋ₓXₓ (with M= Ni, Cu, and X= Cd, Mg, Au, Zn, Ag) cubic compounds are analyzed covering a broad range of behavior between magnetic and Fermi-liquid ground states GS using the it chemical doping: ζ as control parameter. This allows to gain insight into the evolution of the GS behavior including a quantum critical point QCP. Doniach-Lavagna phase diagram limitations are improved by taking into account crystal electric field CEF splittings. Three regions are recognized as a function of ζ: i) a magnetic one with long range magnetic order and T_ord∝ T_N ≈ 1 K, that weakens the interactions between 0.8 K ≥ Tₘ≥ 0.4 K, exhibiting very low Kondo temperature T_K^GS in respective doublets GS. Then, for T_Q≤ 0.4 K, quantum fluctuations start to dominate the scenario with the specific heat C_4f/T(T≥ T_Q) showing T power law dependencies, and a very heavy-fermion it plateau below T_Q. ii) beyond the QCP the typical Non-Fermi-Liquid logarithmic T dependence: C_4f/T ∝ ln(T/T₀), with traces of magnetic order. At the non-magnetic limit: iii) the alloys behave as valence-fluctuation systems with growing T_K that overcomes the CEF splitting. With this experimental information, a realistic phase diagram can be drawn around the QCP where the scenario is dominated by low lying quantum fluctuations, without C_4f/T|_(Lim T→ 0) divergences but a clear drop entering into the non-magnetic phase.