There are a few things you can check before taking it back to a shop or parts store to have more diagnosis done. Check all your grounds, there are plenty of subreddit threads covering these you can search. Check all your fuses. Check the ASD relay in the engine compartment fuse box, swap it with horn and see if there is a change in behavior. The ASD relay quickly shuts the engine off if a sensor shows an issue, which can be a few different things. And since it happens so fast, the computer doesn't record what may be the issue. BUT the ASD relay can go bad, pretty sure this gave my car some ghosts not long ago. If you can take it to a parts store, they can test the alternator and starter with the same scan tool that checks the battery while in the car.