No, just more folklore and myth and historical national pride and marketing than actual truth. The “Ninja” really weren’t a thing until early novelists and folklore made it a “thing”. Kind of like how we hear the emperor was worshipped during WWII. Both are part fairytale and very, very, very complicated to explain in all the involved complications that come with the long history and various ancient regional, cultural, and ideological embellishments from long before Japan was what we know as “Japan”. It’s all just become folklore now due to thousands of years of “stuff”.
I learned some basic ninjutsu from my late brother-in-law, who was a fifth degree black belt in shima-ryu ninjutsu, and quite the character. The vid gives the history of the feud with Nobunaga, and how they became an integral part of the Tokugawa shogunate and helped it get established. Author makes the case that they were similar to the CIA or special forces, and their martial wisdom was substantially similar to what agents learn nowadays because their function is basically the same as the ninjas.