Online Learning for Children

What are your thoughts on using online learning for children? My 6-year old did Waterford Upstart which is an online preschool and learned a lot, but I felt torn because it also led to more screen time and struggles to get off the screen. My 4-year old is signed up this year and hasn't started yet. I'm thinking to not do it to avoid screen time struggles, but would love your advice. I see how technology can be helpful, but don't want my children to be addicted to screens. Perhaps there is a way to get educational benefits, but have limits. Thoughts?