Hey everyone as a reminder, DDoS attacks are rare attacks that affect a typically large portion of the player base because of a coordinated data spam on Blizzard’s network providers. DoS attacks against a single player only happens if you somehow exposed your IP address to a dishonest user (which does NOT happen through Overwatch alone). Typically if you are disconnecting frequently across multiple games and days of trying to play Overwatch, you are NOT being subjected to any sort of attack, but instead have a persistent technical issue with your connection.
Disconnections can happen for a variety of reasons ranging from trying to play on WiFi (connecting directly through ethernet cables is much better), having issues with your modem, issues with the ISP, or connection hub problems between you and the Blizzard datacenter. This is why it is recommended work through standard troubleshooting first and if nothing helps, run a WinMTR test to map out your connection to the datacenter. We can help with any of these steps in the Technical Support forum.
I am personally tracking this problem and providing feedback to Blizzard as I get it. I am also monitoring this thread in the tech support forum which has the most related conversation from Blizzard from it: Random Overwatch Crashes not just me but also the teammates
It is not Overwatch-specific maintenance, just Blizzard Authentication Server weekly maintenance.