Not to be a Debby Downer, but you'd either need a LG TV which is already rooted, or one you can root (per the repo's README, "RootMyTV is unlikely to work on firmware released since mid-2022" and given firmware downgrades are impossible...).
AFAIK firmware updates are opt-out by default, so as long as you connect your LG TV to internet, you're likely to have received one, but I could be wrong.