Usually the non-hierarchical is an option to toggle on/off in the tools I’ve used.
With hierarchy you can still achieve it though. If the topic is “alphabet” I might create major nodes A B C D without linking them. I then play with A B C and D and add more nodes in a brain dump and then re-arrange later and map the relationships
With hierarchy you can still achieve it though. If the topic is “alphabet” I might create major nodes A B C D without linking them. I then play with A B C and D and add more nodes in a brain dump and then re-arrange later and map the relationships