When you have to highlight text and you want to change color you need to go to: Secondary button, Properties, Select the color that is by default and then choose a new color.
I suggest that when selecting the Highlight Text tool a side tab be enabled that allows us to change colors. Attached example of the suggestion
Adobe Acrobat and Reader official update (21.001.20135) containing the fix for this issue is now available. This update will be automatically pushed to all existing installations of Acrobat and Reader. You may also manually trigger the update early by opening the application and going to Help > Check for Updates.
More information about this release is here: https://helpx.adobe.com/acrobat/release-note/release-notes-acrobat-reader.html
Please try it out and let us know your feedback!
Thanks for your patience and support!