Everything I've read suggests otherwise. Ueshiba dabbled in a few martial arts but never really stayed with them long ... until he met Takeda. Daito ryu is the one and only art that Ueshiba stayed with, became a teacher of, and then progressed on his own.
As for "competition", I would research what Peter Goldsbury had to say on that subject. Very illuminating. It's here on Aikiweb somewhere. Basically, there are different definitions of "competition" and Ueshiba was okay with some but not others. Competition between peers to become better - okay. Olympic Judo type competition - no.
Well, I wrote when he thought he was better
, that does not imply that he stayed long. Perhaps what you call dabbling was more than enough for Ueshiba to decide to move on. Mind you he was never looking to master those arts; he was searching.... But I will take your word on it as I have not deeply researched this.
It is this type of competition I referred to, obviously.