How to Change Hyperlink Color in macOS Notes
As someone who's done a lot of UX (user experience) work over the years, I have to admit I was very surprised when I first saw the hyperlink colour in Apple's Notes app. Not so surprised that someone would actually propose it, but very surprised it passed through all the review processes at Apple.

Anyway, I do have a couple of workaround options that may help you until Apple addresses this, as I fully expect they will at some point. These options are far from perfect, but if the default hyperlink colour is enough of an issue, they are worth considering.

Hyperlinks displaying the actual URL

If your hyperlink text displays the actual URL (e.g. "apple.stackexchange.com" instead of "Ask Different") you can do this:


Right-click on the yellow link
From the context menu, select Remove Link


You will notice that the link text now changes to black* and the actual link no longer activates by just clicking on it. However, you can still use it as a hyperlink by selecting it (just double-click) and then right-clicking to select the Open URL option from the context menu. If you prefer, you can also change the text colour to something you prefer.

*If the URL is a full URL (i.e. it starts with http: etc), then you will need to manually change the text colour from the default yellow after removing the link. 

Hyperlinks displaying words

If your hyperlink text displays words instead of an actual URL (e.g. "Ask Different" instead of "apple.stackexchange.com") you can do this:


Right-click on the yellow link
From the context menu, select Edit Link...
This will open up the Link Destination window with the full URL already selected. Copy (commandC) or cut (commandX) the link and click on the OK button.
In your note, Paste (commandV) the URL over the original hyperlink text
Right-click on what is still a yellow link
From the context menu, select Remove Link


Once again you will notice that the link text now changes to black* and the actual link no longer activates by just clicking on it. However, you can still use it as a hyperlink by selecting it (just double-click) and then right-clicking to select the Open URL option from the context menu. If you prefer, you can also change the text colour to something you prefer.

*If the URL is a full URL (i.e. it starts with http: etc), then you will need to manually change the text colour from the default yellow after removing the link.