There is a problem with the Internet in Germany: the Internet exchange operator DE-CIX determined in a survey that German office workers are massively slowed down by Internet delays.
The results apply to office and home office. Poor Internet connections result in an average of 46 minutes of delays per week. If you add this up, Internet problems cost almost a full work week (35 hours) per year.
But at least at home you can do something about the Internet problems. We propose a two-stage strategy for this. Step 1 clarifies whether you actually have Internet problems and shows how you can fix them.
All devices that have a LAN connection can then be connected to the router via cable. Step 2 addresses the issue of WiFi issues. Here you will find tips from CHIP for problem finding.
Real internet failures are easy to recognize, because then nothing works. If one device is offline, grab a second one and see if you can connect to it. If not, continue to the router interface. This shows you the online status.
The basic Internet connection is often fine, but the WLAN weakens. To tackle WiFi issues: