The free tier of ChatGPT is powered by GPT-5.5 Instant, a non-reasoning version of GPT 5.5.

Yes. Go to chat.com in an incognito window and ask it the same question that you ask 5.6-sol with thinking max, and compare. Depending on the question there is or is not a huge difference.

Also, remember the bulk of AI users are using free models, getting terrible answers, and wondering why people keep saying AI is going to take everybody's jobs away.