Understanding vSAN Configuration Types

Hi,

I read that we can have multiple vSAN scenarios, from the default with FTT1 and with other types of FTT (n) which includes RAID5 / 6.

Once the vSAN is configured the first time it is FFT1 standard, right?

Is the FTT type definition based on the policy configured in the VMs?

Is there a vSAN configuration that includes scenario with FTT and type of RAID? Or is FTT RAID the same configuration?

Thank you.