I find using colour very important when taking notes.
To an extent using css to colour bold or italic text helps with the matter but that is limited to only two colours.
Then I started using different headers, made 4 of them the same size and different colour using css, but that only further adds another 4 colours, is still very limited, and honestly just a workaround.
I’d love a feature which would allow me to do something like this: red$Red text$
A syntax which would allow one to pick a colour using a letter, word or rgb value at the beginning of it, and which would then colour the text inside of the dollar signs in that colour. This is merely an example and I’m sure there are better solutions to this if such a feature is even possible.
The HTML suggestions above can be made a little easier with a text expander, such as Espanso. It allows you to configure where your cursor is placed after the expansion which is very helpful for these examples.