Many users of the newest Mac mini with M2 chip are experiencing problems with the reliability of their Wi-Fi connection. There are many testimonials on Apple forums, by MacRumors or on Reddit users whose Wi-Fi connection has very fluctuating and/or too low speeds, untimely disconnections and some also point to declining speeds for the wired Ethernet connection.
It is still a bit early to come to any conclusion, as many factors may come into play. On the other hand, there is no doubt that the media coverage of the case will push the Cupertino engineers to quickly take an interest in the problem: if the glitch is indeed software, we can hope for a quick fix in a next macOS update.