Okay I got some news for everyone with similar problems and just want to make this post because I hear so much about people dealing with it and thinking about quitting Overwatch which is sad bc people are fun.
I got told my modem/ router/ whatever had compatibility issues with the assembly point (that thing where you get your internet from). They said the brand of it has trouble with many SpeedPort Routers (Telekom).
We got it replaced with a FritzBox 7590 and I have to say I got no connection issues since that day.
Here are the links to the topics I created for that problem. Maybe some of the other resolutions will help you too
