A bird that regained its wings only to trap itself back in the cage and lose its wings once more aka Darling in the franXX.
Darling in the franXX, is a Mech/Romance anime and has quite a few issues with its story progression although it's highly intriguing.
The visuals and soundtrack which are this anime are really amazing and the representation of character emotions is also good.
The Mechs have interesting designs and display the female pilots emotion with Strelitzia reactions showcasing how vastly different it's from the other FranXX. They isn't much to the technical side of their operates except for that they
run on a limited resource of magma fuel but the information is really vague. As a mecha fan i feel it would have been a bonus if their operations were broken down yet i would like to believe it's a plot point to reflect the restricted information.
The major issues with darling in the FranXX is how it fails to take advantage of the build up it creates from previous episodes and most notably episode 14 is the biggest offender which in my opinion is the one of the worst episodes within this series as characters are forced to act against their wishes when previous episode showed something entirely different.
More on episode 14 here spoilers : http://prntscr.com/j7kz0z
They are instances where characters act way too forced and seem to abandon their resolve or reflections which they had and creates contradictions to what their end goal is.
The show is slowly going down hill as more interesting routes of the story could have been had but yet the melodrama is forced to play out and ruins the intriguing world.