As a workaround, select any recommendation on Azure Portal and then click View script. Collect all the recommendations you want on one single T-SQL script, each recommendation on a separate batch (GO statement), and run this T-SQL script against your database(s) to manually apply the recommendations.
Please note that manually applied recommendations will remain active and shown in the list of recommendations for 24-48 hrs. before the system automatically withdraws them. If you would like to remove a recommendation sooner, you can manually discard it.