Help my lenovo adroid got it's operating system damaged i think?

because too much malware i decided to factory reset but them malware is still there and i cannot connect google play. It says to fix google play i need to delete host file but it's for rooted phones only so i keep hitting factory reset maybe i get lucky then suddenly there's a pop up to upgrade my lenovo to latest version so i downloaded the 21mb update and then updated failed. Operating system died. So now im trying to download a ROM for lenovo tab 2 a7-30hc but what i saw is 16gb! Wow! My SD card is only 8gb it doesnt make any sense

Read more: Help my lenovo adroid got it's operating system damaged i think?