>>11092709That depends. We talking temporary dopamine? True lasting happiness? Or something that can bring you time-to-time joy?
Immediate dopamine hit? Figurine or action figure you can unbox, admire, then put on your shelf and forget about aside from the occasional glance towards it.
Time-to-time joy? I'd suggest Legos. You can break them down, put them up, and then re-build them later. Or you can use the pieces to try and make something new. Still, eventually you will put them on the shelf and forget about them.
Lasting happiness? Probably not gonna find that in a toy. Best bet? A character that genuinely inspires you to be a better person. Put it in a place that you look at every day and think of why/how that character makes you a better person irl. OR, get a toy that can be used to develop a new hobby or possibly even a skill. Failing that, something that encourages socialization, like a board game or nerf gun or something. Bonding through that can potentially help.
Hopefully that helps.