Thank you. Originally it was set to 0, and i've tried with -1 for both with the same results, the installer does not show as an option and I only see "reset nvram"
I've managed to make it work doing the first installation part of Monterey with an older opencore version, and then replacing it with 0.7.4 to boot again and finish the installation. However, the installer option still doesn't appear in the selection menu.