I'll put our floor plan in for you.
What do we have in the attic: Our children's rooms are a bit smaller. That means the kids (3 and 7) have the downstairs area, where they really play. As soon as something is left unattended for more than 3 months, it goes upstairs. Since the little ones like to come up to the attic, they always find "new toys" there. Then things get swapped out.
Also everything that generally accumulates: camping gear, decorations, children's clothes, documents that aren't needed regularly, seasonal clothing, boxes, etc. Somehow I'm upstairs at least once a week.
With a bungalow, especially in a tight space, you have to store your stuff wherever there is space. And that's not on the ground floor.
Otherwise, consider whether the attic could be partially finished. Then you could also add a work corner.
Then think carefully about how much space the children need. Ours have 11 and 12 sqm. That’s sometimes a bit tight, but it's more than enough for them. I just have to get a bit creative ... Pinterest is my friend and downfall.
