Worldbuilding

It had one huge impact on elf culture which was completely dividing their society into 1) people that isolated and 2) people who wanted to help the other races, guide them in the right direction and such.

Since the "borders" on elf lands went into lockdown, the ones that chose to leave and help also can never return (until far far in the future when a world event breaks boundaries). They also insist on keeping their existence secret for many decades, until the other races are no longer so...combative.

In the eyes of the "inner" elves, they are giving the other races a chance to flourish without putting themselves at risk. They could have killed them all, and considered it, but they chose not to because they were once family. Let them have their chance. There's only so much damage they can do to the world without magic and they cannot enter elf lands without it, so "it's fine probably".

In the eyes of the "outer" elves, the others abandoned their kin and are putting up ridiculous walls. They see them as lacking compassion and often resent them as they made these elves choose. They also often feel the others abandoned their duty.