The Dark Energy Spectroscopic Instrument (DESI) has recently completed its nominal five-year spectroscopic survey. In the first part of this talk, I will quickly review the baryon acoustic oscillation (BAO) measurements from DESI DR2, using over 14 million galaxies within a dataset comprising roughly 30 million redshifts. I will discuss the current status of these results in light of the latest CMB datasets and the Type Ia Supernovae recent reanalysis. I will also highlight prospects for future DESI BAO measurements and the potential of using intrinsic alignments of galaxies to measure BAO. In the second part of the talk, I will argue that potentially departures from the standard theory of gravity itself can be potentially misinterpreted as dark energy, and I will present the formalism we use to test modifications in the underlying theory of gravity. Finally, I will outline ongoing efforts and analysis improvements for modified gravity tests using DESI DR2 full-shape measurements.