Good question; there are probably tips to be shared here, though I don’t have any obvious solutions myself. I also use DA mostly for academic searches, but for some reason I don’t seem to get locked out of Google Scholar, unless I’m just not noticing that I have been. I have a default custom search set for articles that includes Google Scholar alongside JSTOR, jurn.org, and my own university’s library catalogue, so it may simply be that DA is capturing some of the same items by other routes. I suppose the test would be to uncheck Google Scholar in the Search Sets => Plugins tab and see what happens. But I suspect many others here, particularly outside the Humanities where I’m confined, have their own deeper experience and tips to contribute.
For what it’s worth, here’s are screenshots of my default settings for my basic academic search set, first from the Plugins tab (built-in DA plugins):
… and then from the Sites tab (third item is my own institution’s library catalogue, for which you’ll substitute your own):
I don’t have any user plugins in this search set, but there may well be ways to exploit some of these resources more effectively than I’ve yet found, as well as other aggregators of Open Access outlets that would be useful to incorporate.
I think I probably speak for all academics when I say that PubMed is in a league of its own as a DA-friendly resource and a utopian model for how everything else ought to work. (But a shoutout also for DA as a tool for finding, aggregating, and sorting relevant Wikipedia articles in a single synoptic document – I don’t know any other tool that can scrape Wikipedia so usefully.)