You need a one-time setup of an additional "command", then you'll have an easier process.
Select EPUB book settings
Scroll down to "Text Selection Menu" and select it
Hit the "Plus" at the bottom of the screen
Select "Built-in command or preset"
Stand back a safe distance as a huge selection of options appears!
Select "Highlight selected text and edit" - this will let you highlight and create and annotation in one easy step.
The "options bubble" will now have the "pencil with plus-sign" icon. The next time you select text, choose the "pencil +" icon.
As you can see, there are many "Text Selection" options. You might want to selectively try them to determine which ones you find useful.
Marty