WCAG indicates roughly: buttons are for starting actions, links are for navigation.
What to do when I want to start an action, the app first navigates to a page where the user configures action settings and then start the real action?
The intention and context is: it is a very important action.
Just putting a link "Start action" (with a better name) by a simple link does not give a link sufficient importance. The 'start action' should look like a button to show that something important can be done.
Is it OK to use a <a class="btn btn-success" ... >?
More black-and-white answer: Will using an '<a class="btn btn-success">Call to Action</a>' pass the level AA tests?
So, I am NOT looking for an opinion-based answer. I hope you can give good advice so I can help people.
Of course aria attributes are added to make this 'start' very clear.