I have circled back to using the apps that are already on my phone, especially the Apple Reminders app which I am currently trying out as my main notes and ideas system.
I have placed it as one of the two bottom widgets on the lock screen which gives me immediate access to everything I need to capture a thought: a main note, the list where I want to store it (e.g., work or personal), the notes field if more context is needed, and I can flag it or schedule a reminder. The app then also has an optional auto-categorize feature which works quite well. Add to that reliable sync across devices and except for a good way to bulk export lists, this has everything I want from a quick draft and capture system.