Assuming that the WiFi really is up, just wait a while. Eventually the cameras will figure out that it’s back and most should reconnect.
Now it gets strange. If events are being recording, it sounds like the cameras really did reconnect to the WiFi. Sounds like maybe the internet or WiFi is performing VERY slowly. Uploading to the Wyze servers is a data transmission and does NOT have to be done at real time speed. So if your internet is barely functioning, the data upload will work, but you will not be able to get a video feed because that DOES need to be in real time speed.
Don’t try to connect to the camera and watch live video, but rather select the camera and immediately hit the gear for settings and attempt to reboot the camera from the app. That won’t help if it’s really the internet that is slow - which I suspect is the case - but it wont hurt to try.