I’ve taken a lot of meds over the years. One of the ones I was on for a long time was quetiapine xr (seroquel - the slow release version). The ordinary release just hit me like a tonne of bricks, turned me into a zombie and made me gain weight. But the slow release version gave me some of the cognitive quieting without the unwanted side effects.
The trade off was that it turned down the cognitive volume generally - not just with my parts. So it messed with my concentration, made me tired, and gave me some emotional flattening (which tends to mess with my motivation). Even on just the slow release version.
I was on it for a long time, and it definitely helped me manage through my most chaotic years. I still had to manage my DID, just not quite as amplified as it was.