Append current date to the filename via Cron?

In the Cron Job section, if a variable is inserted, the Cron Job cannot be modified, it is no longer visible and does not work. Is there a way to insert variables like from the command line with crontab -e?

bash /home/user/bash/ > /home/user/log/script_$(date +\%Y\%m\%d).log

This query better suits in stackexchange…

In the HestiaCP Cron Job section the insertion of variables is not allowed. After saving if you reopen the cron job it disappears.