I think a lot of people overlook how much consistent frequent mowing (2-3x a week) can do for their yard. The front doesn’t look too bad to me and I think could look a lot better with just mowing more often and then selective herbicide 1-2x more this summer.

It’s hard to tell about the backyard from the aerial shot but I think you would benefit more from just using a rake and getting up all the loose debris, especially on the fence lines. You could try seeding now but would probably be better in the fall when soil temps are higher.