How to make lookup data editable?

I am building an innovation traject I have into a Glide project.
People first write and score their ideas.
After that they make onepagers of the idea.
The columns name, header and description should go from the idea table to the related onepager table and be editable in the onepager.
Of course I can lookup the three via a relation. But then it’s not editable. How do I make it editable? I assume I have to copy into a new column but how and with what?

You could create a Single Relation back to the table that contains the source of the lookups, and then update via that relation with a Set Column Values action.

I might choose the for me simpler route: not different tables for ideas and one-pagers, put one table with all and with visibility components based on the phase the project is in (idea / one pager).