Raspberry pi USING ubuntu server 20.04.1 having read only file system and no permission! unable user root or sudo

Im stuck with read only file system and i unable to use root permission which
give me

sudo: unable to resolve host ubuntu: Temporary failure in name resolution

i cant even edit fstab < which cause the error. Everytime i try to use fshk it also require root. T_T

stuck in a loop

HELP