I also think that time might pass faster when the PATHS dimension is not in use, to counteract the eternity that seconds last when it is. This is probably why big groups of Titans made at once, like in Ragako village, had more deformed ones than usual.>>191695083
I think Abnormals are an emotional thing, since Ymir confirms that being a Titan is a semi-conscious state with vague memories. Presumably, most of those transformed would be angry and scared, making normal titans, but those who aren't are Abnormals.
This would be why Dina ignored Bertholt for the Yaegers, and killed Carla before eating her; her last thoughts were of finding Grisha again. Likewise, Rod's last thoughts were becoming the Founding Titan, which is the ruler of the walls, hence why he went towards the nearest big district instead of attacking towns or the SC