lawful73

Only if your ISP supports ipv6 and you use it, not the case for most people. 

That's perfectly normal. Your computer will see your router as DNS server, and the router will forward the request to 1.1.1.1. Exactly how it's supposed to work. 

Okay so your modem should be in bridged mode which is used when you are passing the signal from one router to another so its not so bad that its in bridged... now it depends on how you do the DNS test because if it is locally on your PC it will come up as your router in most cases. What you can do is https://www.dnsleaktest.com run the test on that site and if the results come back as Cloudflare then you are using cloudflare as your DNS otherwise the other modem/router is filtering it but go ahead and try it 

Whenever you are trying to understand I.T concepts, comparing it to real world examples makes it a lot easier to understand. Just think of your I.P experiencing packet loss as similar to Amazon Delivery losing a shipment on its way to its destination. 

Think of packet loss as when an extremely brief power surge/outage happens. Suddenly everything is alright then you notice your lights flicker and your speakers turn off. If it lasts for around a second it can even turn off devices and generally is not a good experience.
 
If you are simply uploading files to the cloud (service like Google Drive, Photobucket, or Dropbox), most of them are smart enough and have mechanisms that would re-transmit the "packet that was lost" though you would notice it may take longer to send the file by a bit (depending on how much packet loss there is).
 
If we are dealing with calls/ video calls, you would notice some choppiness, pixelated videos, loss of audio, loss of video, or similar issues. It all depends on the application you are using.
 
Packet loss can be caused by a bad network card, a poor wireless connection (far distance or interference like microwaves or elevators), modem issues, or even ISP (Internet service provider) issues.
 
Hope this helps!

Packet losses are the worst affected when transferring audio/video call packets as it could cause a more of a disturbance on call. In regards to video or picture quality, doesn’t affect it at all as any lost packets are resent unless you are taking about very high packet loses, where you could notice decrease in speed, unresponsive uploads etc.

Packet loss affects speed because lost packets need to be resent. Actual missing packets could affect anything