Like if I have a 10TB and 2TB drive, can I create a 2TB raid1 partition for important data and a 8TB partition for data that does not need to be backed up (Such as steam games and other easy to recovery things)

I tried to look it up myself and found things saying drives of different sizes can be raid1 together, and that the raid will be the size of the smallest drive, but I can’t figure out if the remaining space can still be used for things