I have used Notability but it tends to crash a lot. There are a lot of weird quirks with it though and I tend to use it on my computer so it limits my use.

Notion is confusing as hell but I feel like its very useful once you get over the learning curve.

I really want to try Obsidian. It reminds me a little of Scriviner.

I still haven't found the ideal system, but I think there are some great places to start.