All of the information you've posted points to a issue with the VPN, especially since other WiFi device work fine during VPN outages. Perhaps your company's IT people can help figure out why the VPN keeps dropping; they will know best how it's configured. It could also be something about your WiFi that is causing the VPN to drop, even interference from neighbor's WiFi equipment.
Have you been able to run an Ethernet cable between the router and the computer? That remains an excellent way to determine if WiFi issues are contributing to the problem. And it doesn't require much technical knowledge; just plug it in and see what happens.
Have you been able to observe the lights on the router during a VPN drop? That is another easy method to determine internet and WiFi status. Look back at my earlier post with a description of the lights and let us know what you see.