Hello,
Here a simple App, a task list, a Gantt view and a forms.


You will need a SP list named Tasks.

Priority column values : Low, Medium, High
Code to look
- In DatePicker OnChange, nice usage of sequence
- Gantt Bar : X, Width, Height
- Warning, I used label to store "gallery line variable"
PS:
App design contains SVG integration
Proposed by my company : umlaut