Does the insouciant spell really work If not what is a spell that works for real?

No spells will work. They are not real.

Another Opinion
Spells are complex things developed by practitioners with years and years of experience, research, and practical experience.

Most spells are things we do for ourselves, although some are done at the request and for others.

A transformation spell, one that changes a person or thing into someone/thing else, is not practical, ethical or in this case possible.

This does not mean that there are no such things as spells, just that this particular transformation spell does not.

Much as it is wonderful to wish and imagine life in some other form, the dangers and difficulties vastly outweigh any "fun" you might perceive.

When you are born into your human form, it take nine months for you to develop your form, and then years and years to learn to live within that form.
Babies aren't born walking and talking and knowing their language, culture, history and basic social etiquette.

Transforming into something else, even if that something else was not a mythical creature, would mean horrible pain, and trauma to your body and mind.
Then you would have to learn all the language, social interactions, taboos, etc. not to mention the motor skills to even basically function.

It is better in the long run, to find ways to be happy and enjoy the form you currently inhabit. Use your imagination to "play" with the ideas of being someone/thing else, and find ways to fulfill your reason for being born into this form.