30-min block intervals on schedule

I go to bed at 11 every night and wake up at 8 every morning. I have a big issue with scrolling social media right before I go to bed and right when I wake up, so I tried setting a schedule. But when I went to create a schedule the options for time were limited. Right now I don’t have a schedule for before bed because 10-12 feels too long and in the morning my schedule is 7-9, which also feels too long but it’s better than nothing. If I could do 10:30 pm to 8:30 am that would be perfect.