Daredevil Born Again
Most likely very early 2026, some filming pictures showed a New Year Eve ambience. Fisk is most likely already mayor, and New York mayors election always happen in November the year after the Presidential Election. So it could be after Ritson or after Ross. I think Ritson because Echo, happening early 2025, show Fisk being interested in the next mayor election, and Ritson was elected in November 2024. So Fisk got elected in November 2025.
Ergo, DD:BA is most likely set in January 2026.
Captain America : Brave New World
I think that the Ross election immediately follows on the impeachment of Ritson, placing the election after 2026. We see cherry blossoms in the trailer, which could be the National Cherry Blossom Festival at Washington D.C., held in March 27.
This festival is about geopolitical relation between U.S. and Japan, and we know it will be an important theme in the movie, both countries competing to mine Tiamut's adamantium. So it would make sense to show this festival.
So I bet for a March 2027 placement.
Agatha All Along
Like you said, the corpse found by Agatha has a tag that say October 13, so it's a safe bet.
But for the year, I think it has to be the sooner after Wanda dies, not too long. Wanda died in 2024, so October 2025 seems to be a good placement.
But Marvel Studios seems to prefer placing their project the most recent they can so I guess October-November 2026 could also work.