We study the Klein-Gordon (KG) oscillator in a cosmic string spacetime with a uniform cosmic screw dislocation (torsion). We start with a confined (in a Cornell-type potential) KGoscillator and report the torsion effect on the exact energy levels. We observe shifts/dislocations of the energy levels along the torsion's parameter δ-axis by δ = ℓ/kz; ℓ = 0, ±1, ±2, • • • . Such energy levels shifts/dislocations manifestly yield energy levels crossings (i.e., occasional degeneracies). Moreover, we observe eminent energy levels clusterings when |δ| >> 1, for each value of the magnetic quantum number ℓ. To find out parallel systems that admit invariance and isospectrality with the confined KG-oscillator, we discuss the KG-oscillator in a deformed cosmic string spacetime background with a uniform cosmic screw dislocation. Such parallel systems are found to inherit the same effects as above. Yet, we suggest a new recipe for position-dependent mass (PDM) KGoscillator using the PDM-momentum operator of Mustafa and Algadhi [38]. Two PDM illustrative examples are used, a power-law type PDM, and an exponentially growing PDM. For the exponentially growing PDM, we show that such a PDM introduces a Cornell-type confinement as its own byproduct. Hereby, we observe clustering of the energy levels, as the PDM parameter ξ grows up, but no energy levels crossing are found feasible for a fixed torsion parameter value.