No of course you can't opt out of the social credit score.

what you watch on it is absolutely used to adjust your credit score.

And yet another bold claim that you are even being so bold as to say is absolutely true. Do you have evidence for this one, either?

I'm asking you to defend your claim that not using TikTok specifically affects your social credit score.

So no, i don’t have a direct source that says “you must use this app or your credit score goes down”, i have a reasonable informed idea that it probably does, based on china’s current treatment of it’s citizens.

This absolutely doesn't follow. Can you elaborate on your logic here? There is no obvious line of reasoning from "china's current treatment of its citizens" to "TikTok is mandatory". Your imagination is not evidence of something.

Why, do you happen to a single or any even tangentially related source pretending it doesn’t?

I'm not the one asserting that failure to use TikTok negatively affects your social credit score; no, I can't find a source that explicitly states "not using TikTok doesn't affect your social credit score", because that's not how this works. You make a positive assertion you provide evidence to back that up.