The age of consent in America is not 18 everywhere. It is set by each state and ranges from 16-18. From Wikipedia:
While the unrestricted age of consent is between 16 and 18 in all U.S. states, the laws have widely varied across the country in the past. In 1880, the ages of consent were set at 10 or 12 in most states, with the exception of Delaware where it was 7.[104] The ages of consent were raised across the U.S. during the late 19th century and the early 20th century.[105][106] By 1920, 26 states had an age of consent at 16, 21 states had an age of consent at 18, and one state (Georgia) had an age of consent at 14.[104] Small adjustments to these laws occurred after 1920. The last two states to raise their age of general consent from under 16 to 16 or higher were Georgia, which raised the age of consent from 14 to 16 in 1995,[107] and Hawaii, which changed it from 14 to 16 in 2001.[108]
The primary source is a leaked podcast script from a podcast run by an anonymous celebrity gossip Instagram account which was posted on reddit. This is basically the journalist equivalent to using 4chan green-text as a citation. The article, which fails to verify anything, is a year and a half old and not a soul related to the production has corroborated any part of it in that time.
No official statement was made about why Cavill is no longer on The Witcher. I wouldn’t doubt that he was being difficult on set considering his love of the source material and how little the show respected it. I also wouldn’t be surprised to find out his contract just ran out and neither party was interested in renegotiating.
James Gunn has specificly said, on thar record, that Cavill wasn’t fired. The next Super Man is just going to be younger. After how badly Black Adam flopped, I’m not surprised they’re taking the DCU in a different direction.