You are not getting any performance at the level of Apple's M1 chip. Realme Book comes with Intel Core i3 11th Gen or Core i5 11th Gen processors.
Great news is that the laptop does not come with annoying bloatware that you may see with some budget laptops and Realme smartphones.
If I had to guess, I would assume Realme is trying to get the attention of the enthusiasts by making it extremely cheap and looking like a MacBook ripoff. The free marketing gained through price to performance ratio should offset the lost revenue of pricing the device much cheaper than the competition.
Unboxing Realme Book (Slim)
Lowest pricing I came across my initial research was equivalent to $616. These prices were from India. You may have to import the device or ask a friend visiting the available region to purchase one for you.