I think the most accurate way would be to model the bolts by solid elements, assign a pre-tension section with a corresponding surface (a cut surface inside the bolts shaft). You would then tighten the bolts by a defined load, lock them, and assign a load. You can output the stress by looking at the respective elements and the force by RF of the pre-tension node.
See https://abaqus-docs.mit.edu/2017/English/SIMACAEPRCRefMap/simaprc-c-pretension.htm