In this work, we derive lower mass bounds on the Z′ gauge boson based on the dilepton data from the Large Hadron Collider (LHC) with 13 TeV of center-of-mass energy, and forecast the sensitivity of the high-luminosity LHC with L=3000 fb-1, the high-energy LHC with s=27 TeV, and also at the Future Circular Collider with s=100 TeV. We take into account the presence of exotic and invisible decays of the Z′ gauge boson to find a more conservative and robust limit, different from previous studies. We investigate the impact of these new decay channels for several benchmark models in the scope of two different 3-3-1 models. We found that in the most constraining cases, LHC with 139 fb-1 can impose mZ′>4 TeV. Moreover, we forecast high-luminosity LHC, high-energy LHC, and Future Circular Collider reach, and derive the projected bounds mZ′>5.8 TeV, mZ′>9.9 TeV, and mZ′>27 TeV, respectively. Lastly, we put our findings into perspective with dark matter searches to show the region of parameter space where a dark matter candidate with the right relic density is possible.