I am not an Coffee expert so can’t tell you what’s more secure. I think there are lessons you can take to roast yourself wich will help you avoid those carcinogenic being created but would also guess that they will tell you to get better equipment for that and to not just an oven as they are to inconsistent.

True but they have to measure the amount and stay below a threshold. You can’t guarantee that if you do that at home.

The problem with roasting your own coffee is that you don’t have the equipment to control temperature and time precise enough to make sure that no acrylamid or furan is created. Both of those substances are carcinogenic and should be avoided. If you buy roasted coffee it’s always made sure that it is not containing that stuff.