My bike came with an 80mm travel fork. I haven't found any 80mm fork online; the lowest travel is 100mm. I asked the support team if I can install a 100mm fork in it and they said it would void the warranty since it's beyond the 10% allowable travel increase. I looked around and found out that going beyond the travel the bike came with would put strain in the head tube and change the bike's geometry.
That being said, are there any good 80mm travel forks out there that won't change the stack height, bb drop, and the head tube angle?
EDIT: Following Klaster's answer, I found this neat little listing from rockshox. It lists the 30gold with 100mm travel as 473mm length and the sektor with 80mm as 474 length. According to the specialized page, my current fork length is 475mm (I assume this is the same is ATC). This means that either of those two won't change the geometry of the bike.