There is many points in your question. A couple of ideas on how I would proceed. I would invite team to get focus (if not already in place) so you could at least complete 1 story. Ensure that bugs are handle following the Story priority so fix whatever is broken in your oldest story or higher rank before moving to other bugs. I would have team inspect the type of bugs if they were avoidable; Are they requirements understanding issue, is there use case not covered tought of before developping, etc. I found that using the “3 Amigos” or Story Kickoff so the BA, Dev, QA sits together to ensure they understand the story before starting it. It help see many angle and think of edge cases that can help during design etc.