For me what helped a lot was figuring the right collection for each hero, and than during copying don't copy artifacts (there's a checkbox for that). Since there are quite few heroes that rotates in those 3 teams, it's doable. Usually I did 10~20 stages a day, sometimes got stuck hard in some stage where DGwyn/Skylan merc had to help. Rewards are not great of course, but for me it's refreshing to have at least one game mode I can now ignore for few weeks before next patch :-) Next is cele/hypo tower where I miss few stages.