Neymar, who once graced the books of Clasico rivals Barcelona, has long been linked with a switch to Santiago Bernabeu.
Interest does, however, appear to have waned slightly in the 27-year-old as potential alternatives have emerged.
Among those is the Brazilian’s current club colleague Mbappe, with the World Cup winner very much one for the present and future at just 20 years of age.
Neither he nor Neymar would come cheap, but Madrid are expected to hand Zinedine Zidane a sizeable transfer war chest this summer.
No player is considered to be out of their reach, but Del Bosque has urged his former employers to think carefully before making any recruitment calls.
Quizzed on which of the two superstar PSG forwards he would look to sign if still in charge of the Blancos, Del Bosque told Radio Marca and El Partidzao: "I'd sign Mbappe because he seems more sensible.
"Neymar even imitates children throwing himself around."
Whether it be Neymar, Mbappe or someone else, Real are in need of inspirational signings during the next window.
The 2018-19 campaign proved to be a forgettable one for all concerned in the Spanish capital, with just another Club World Cup success to show for their efforts.
The Blancos got through three managers during a troubled season, with Zidane eventually returned to the helm a matter of months after walking away on the back of a third successive Champions League win.
“They've an excellent group but the results didn't come,” said Del Bosque.
“Changing a coach twice is one of the worst things that can happen to a club.
“All three knew Madrid, but things happened.”
Del Bosque’s successor as manager of the Spain national side, Julen Lopetegui, had started the season in charge at the Bernabeu.
He was relieved of his duties on the back of a humbling 5-1 defeat to Barcelona in October, with Santiago Solari faring little better as he was also sacked in March.