How can you tell if someone is cutting you off from a Wi-Fi connection on your laptop or is it just a weak Wi-Fi signal?

I need your knowledge and/or opinions about this since I'm concerned if someone doing it or the Wi-Fi signal ain't strong. So my laptop is connected to Wi-Fi that I do not own(they know that connected to it though and they know it's me) and I'm just watching Youtube videos then after like 7 minutes, I got disconnected from Wi-Fi. When that happens, I just restart my laptop and it auto connects to the Wi-Fi. The fastest that I got disconnected is when the moment I open my Google Chrome browser. My laptop is near to the modem/router. This is happening like when I feel lie it's coming and it's kinda fast. Here are my questions about this:
1. I use an add on VPN for my google chrome browser, does this affect my connection?
2. They use an Apple iPhone. Could it be that they're disconnecting it from the phone?
3. Does a USB Wi-Fi adapter help and is there a USB Wi-Fi adapter without needing to put Wi-Fi info?
4. Is there any software that can help me detect if someone is cutting me off from Wi-Fi connection?
5. Maybe there's an app they use that can disconnect you from Wi-Fi?
6. What are my defense options?
7. Maybe it is because of the brand of the laptop?

I've burnt out of questions for now, but there must be more. Please help.

I also just saw that my internet connection got disconnected then reconnected again in just like 1 or 2 seconds.

If it's not your own Wi-Fi router you are connecting to, your connection may have a time limit. This is normal especially with publicly accessible Wi-Fi hotspots.

If it's your own router then go ahead into the settings and set your own connections to unlimited (there's actually none but you can set it for a very very long time). While you're there, set it up so that no one else can connect with you so you can use the whole bandwidth of your internet connection.