Actually there 1 every months, and about same for apps. So no, they are not slow. The problem is that the updates barely solves the issues or add real improvements.
For example, update of the camera has been to add tooltips... but i didnt see real improvements for the camera itself. All problems like over sharpening textures, or high brightness by default, or pro mode lack of features are still there.
3Dscanner app did not improve at all.
Full firmware update did not solve many of the bugs that have been reported.
Maybe Samsung is focusing more on Android 10 now. And imho that would not be a bad thing.