mine-imator huh, i never used that but i heard of it, dunno if its possible to make the animations smoother since i think they are not manually made by u or other users (made by the app devs, i think - again), but if u want more detailed animations u gotta use blender, as plasma studios does, but its more complicated, and dont compare urself much to those professionally made minecraft animation vids on youtube, those dudes trained on blender for years so ofc the animations will be "modern", but as for you i guess mine-imator is a good start to begin getting familiar with animation 3d-animating in general, never give up (i already did lmao-)