The Gaia mission detected many new candidate beta Cephei (beta Cep) pulsators, whose variability classification has since been confirmed from Transiting Exoplanet Survey Satellite (TESS) space photometry of the nominal mission. We aim to analyse all currently available TESS data for these beta Cep pulsators, of which 145 are new discoveries, in order to exploit their asteroseismic potential. Although they are of critical importance to improve evolution models of massive stars, beta Cep stars are under-represented in the current space photometry revolution. We extracted light curves for 216 stars from the TESS full-frame images and performed a frequency analysis by means of pre-whitening. Based on Gaia Data Release 3, we deduced the stellar properties and compared them to those of known beta Cep stars from the literature. We developed a methodology for identifying the dominant pulsation modes of the beta Cep stars from the detection of rotationally split multiplets and Gaia and TESS amplitude ratios. We used grid modelling to gain insights into the population of beta Cep stars. Combining TESS and Gaia, we successfully identified the mode degrees for 148 stars in our sample. We find the majority to have a dominant dipole non-radial mode. Many non-radial modes show splittings in their TESS frequency spectra, which we used to calculate their envelope rotation, spin parameter, and the level of differential envelope-to-surface rotation. For the last, we find an upper limit of about 3. We also provide relative frequency asymmetries within the multiplets, ranging from -0.15 to 0.15 with most being positive. Based on grid modelling, we provide mass, convective core mass, and age distributions for 119 stars. Our sample enables asteroseismology of beta Cep pulsators as a population. Our study prepares for future detailed mod- elling based on individual frequencies of identified modes leading towards a better understanding of these massive pulsators.