Second versions oftentimes mean a second SKU or second game. Assetto Corsa confirms it's a new game because for their slide they make sure to make a distinction between second version and updated version. The slide for that IP mentions "second version" for 2024, but there is an updated version of their most recent entry planned for this fall which is not listed. If it really was about updates, that slide would be mentioning the PS5/XSX version of Competizone for this fall, but it's also talking about the original Assetto Corsa when talking about a second version, an eight year old game, meaning it's talking about Assetto Corsa 2 (Competizone is a licensed GT3/4 focused spin-off so this isn't actually AC2). Assetto Corsa already released a second, updated version with all of its content some years ago.
It's absolutely a new game.