I would recommend going to Task Manager -> Startup tab and checking what services you have enabled. If you get notifications just after restarting the computer with no browsers running or anything else explicitly started, you may have some of the bloatware installed (often comes with the new computer itself) and these might be legit notifications. Then going into the Edge settings and seeing that you may have a recent website added with 'allow notifications' on it. When you get into this state or you are reading this because you 'googled it', the key is not to interact with the notification (do not click on 'remove virus' or whatever it might say and understand where it might be coming from).
All 'scary' notifications contained the same website name. For Edge pop-up notifications, EACH of them contained the name of the website under the notification which helped me identify them as such. One point I will add to the above: website popup notifications are often made to look like legitimate Windows notifications and hence it is hard to tell if it is real one or not. Similar thing happened on my wife's computer. Note: instructions for Edge at this link are irrelevant as they refer to Edge Legacy
