I tried 5L for my flight. Well, for part of it. There were young children in row 6 and, as kids are, they were not particularly quiet when awake. I have no issue with kids at all. They were very cute but I wanted a quieter area. Luckily 9L was empty so I eventually moved there. I think I also like 9L because I can't see the person next to me in 9G at all since the row is not staggered and the seat next to me is not angled. In 5L, I could kind of see the person in 4G because the seat was slightly ahead and angled.
While people waiting for bathroom can see 9L, I rarely saw anyone wait or even wait and stand in a position where they would look into the seat. I did not have any issues hearing noise from the middle galley while I did hear noise from the front galley in 5L. 5L was definitely good but I think I will stick with 9L going forward (assuming available).
Thanks for all the advice! And I appreciate these are very first world problems. I am happy I get to fly business at all. Not a given for me so I definitely try to make the most of it when I do.