Metal-organic frameworks (MOFs) offer excellent structural tuneability that enables selective host-guest interactions, but integrating them with conductive substrates like Ti3C2Tx MXene can reduce accessibility to functional groups. This work empirically analyzes the influence of synthesis strategy on the electrochemical performance of amino-functionalized IRMOF 3-MXene hybrids for dopamine (DA) sensing, restricting their availability for DA interaction and reducing sensing efficiency. In contrast, the post-synthetic hybrid retains free –NH₂ groups, enabling effective DA preconcentration, which allows subsequent electron transfer to the conductive Ti3C2Tx. This results in enhanced electrocatalytic response, with a synergistic index of 1.12, high sensitivity (263.8 µA mM−1 cm−2), and a low detection limit (56.4 nM) towards DA detection. The Schottky barrier formed at the MXene/IRMOF 3 interface modulates the charge transfer dynamics. Theoretical adsorption energy calculations further validate the experimental observations, highlighting the critical role of free and accessible functional groups in optimizing host-guest interactions for enhanced electrochemical performance.