To set date and time #

[email protected]:~# date --set="20211229 15:35"

output

Wed Dec 29 15:35:00 UTC 2021

To set the hardware RTC #

[email protected]:~# hwclock --systohc --utc

now reboot the device and check for date and time

[email protected]:~# date
Wed Dec 29 15:35:28 UTC 2021