I agree Davit, I think the behavioural element is easier to engage with, albeit its going to be about forms of exposure & confidence building with such as Behavioural Activation (doing more stuff to us laymen!), as we tend to learn a lot through doing. The cognitive side is harder to make work just like how acceptance is very hard to actually perform as it doesn't seem to work for a while.
Stacking seems a good one. The only thing I think that would need care would be the tendency of those of us with OCD to createa ritual out of a healthy behaviour, so perhaps altering the theme would suffice.
If thats the bubble shooter I'm thinking of, yeah it tends to throw alternate colours out so it can take more than a few tries to get rid of the last one.
I noticed you talked about your home life on another thread. You seem very isolated in your region so how did that help or hinder you? Was it a real problem and anxiety ate away at social skills or was a a boon because you were very self sufficient and had to carry on regardless?