That's a lot of gum you chew a day. But definitely still tobacco. You get more microplastic from other source than chewing it, but you get 100% of nicotine from smoking.

tobacco, obviously. You also shouldn’t do drugs, vape and drinking (too much) etc

Definitely smoking gum.

If I'm not wrong there are non-plastic based gums available too, sure they are expensive but if you are concerned about mixeopastics you should comcder that option

bold of you to assume tobacco smokers only smoke twice a week

Well crap, I never knew there was plastic in gum. How is that legal? https://www.ecowatch.com/plastic-chewing-gum-2653209141.html

Username checks out. But yeah, ofc it is tobacco.

There is no such thing as 'more deadly'. The adverse effects of smoking to your health are known. The adverse effects of nanoplastics and accompanying compounds are less well known.

If you are concerned with your health than actually be concerned with your health, stop doing unhealthy shit with any frequency. Eat plantbased, exercise, get yourself checked out at a doctor, do a blood test. You know what a healthy lifestyle looks like. Do that.

Otherwise do whatever you want. Go crazy.

Smoking what? Tobacco? Or based on your user name, weed? And if weed, by what method? I'll assume joints.

In terms of greatest harm I'd guess

Tobacco x2 week > Sugar chewing gum> Joints x2 week > non sugar chewing gum.

If that's 10 a day sugar-free gum it will destroy your intestines eventually. If it's sugary it will destroy your teeth. Smoking twice a week is probably even less harm than inhaling cars exhaust on streets everyday.