As someone who has a bit of medical knowledge (I'm not a doctor but I know a bit), living that kind of lifestyle will likely lead to worse pain and won't guarantee death. Don't do it. You probably won't die, but just experience crippling injuries and pain throughout your life. Our medical system today is so good that we can save people who get hurt through these things.
• smoke and drink heavily - will lead to lung and liver damage, you'll have to haul around an oxygen tank for COPD or end up on months of chemotherapy for lung cancer. Liver failure is also not pleasant as well.
• use a motorcycle or a very dangerous car - neither of those are very likely to kill you, but they are likely to cause you very severe and painful injuries and possible disfigurement of your body. Again, medical technology is too good nowadays, you might survive a motorcycle crash but you'll be in the ICU for months and live the rest of your life in pain.
• eat only fattening foods - you'll get diabetes or heart disease. Neither of these are really lethal in the short term and you'll end up on insulin or unable to walk up stairs from a heart attack. More pain, not death.
• live a sedentary lifestyle (which I already do) - isn't going to increase your chances of death alone
• not follow covid regulations (no hand washing, no social distancing, etc) - if you're young COVID will not kill you. It's only dangerous for elderly or weak individuals. If you got COVID, it would probably be like a nasty flu.
• engage in risky sexual behavior - we have so many treatments for STIs that they're not going to kill you for a long time. This includes AIDS. Getting STIs will just make your life more miserable and painful.
• live in a high-crime, high-violence area - it's very, very unlikely that you will end up dead from violence or crime. However, you can get beat up or injured, which will again just lead to more pain.
Living a worse or riskier lifestyle is not a great way to shorten or take your own life.