I memorized the first 100 squares, to me its easiest to memorize as rote and active recall, its easier to me , and I don’t succeed much with mneomnic or palaces

i have 2 questions

the first 100 squares is just 358 digits, not very long to be very hard in few days maximum

but I am planning to expand this to the first 1000, its 5544 digits, how much hard you estimate it is ?

second question : I considered myself as born with good memory, so why it easiest to me rote and active recall and I don’t success good in mnemonic and palaces ?