It would very convenient if KNotes supported markdown styles to create headers, itemized lists, etc. This would also require a new button or tab to switch between the input and the rendered pane.
KNotes is no longer maintained since 24.08. Please migrate to Marknote. https://apps.kde.org/marknote/ See https://invent.kde.org/sysadmin/release-tools/-/merge_requests/53