Need help trying to fix these

Welcome to the forum. Suggest visiting a dealership or equally equivalent repair shop for a thorough/proper diagnostic.

It looks like all of those codes are from the ECM. Considering all the things that module has to do, my first thought is that the ECM might be OK. Sounds like data is moving around as it should. You could disconnect the negative battery cable for a while (like 1 minute) to force a system reset. All the engine an transmission adapting will default back to square 1 to start a total relearn based on your driving style. Then see what faults return if any. That would at least give you some info to present to a shop or GM service location if further checking is necessary.

Buy yourself a $100 code reader and try resetting the codes.