The phone in question has smooth animations. They're just very slow as if to show how smooth and cool they are. It's also from a very well-known brand. I could double animation speed with developer settings but even with this I felt like animations were too slow.

Solution was to disable animations. However this sometimes breaks things. For a few month this broke multi-tasking (two apps on the same screen), but the vendor fixed it (though they reworked multi-tasking at the same time to prevent switching one app so it became almost useless for me at the same time)

Unfortunately I like having the ability to install what I want too much to get an iPhone but I understand how people valuing stability may prefer it.