Hello there,
Also in Year 11 and you seem to be having the same dilemma I was facing a few days ago. (Deciding between 4U Maths or Chem, I chose Chem :O)
Anyways, you seem to be a 'creative' student since you're taking a wide range of subjects in various industries. Chemistry gets really specific in Yr 12, definitely hard if you don't persevere, but it depends on your personality. If you're the type of person to grind out study sessions, be easily motivated to work daily, and be willing to pay money for tutors, choose Chemistry.
BUT
If you like assignment-based subjects which you have a lot of time, thought and creativity to put into it, choose ITM. Personally, I would choose chemistry since a strong textbook, tutor (if possible) and dedication can get you far, especially with its scaling. Many courses provide bonus points for chemistry so yeah.
TBH, I don't have a chem tutor because I already have one for 3U and physics but tbh, if I worked much harder, procrastinated 20% less, I wouldn't even need a tutor. It's just good to get ahead of the content.
Hopefully this helps, dw if you can't come to a decision today, or tomorrow, or in a week. It took me 2 weeks and a couple of hours to determine between 4U and chem. Time, that's all it takes.