Don’t use Ubuntu 20.10. If you use non-LTS releases, you have to be someone who loves to upgrade OS’s at least once a year. I have been that person, but I am not now.
And if you’re trying to run a standard install over a wifi connection, welll, that doesn’t seem like a good idea either.
But connect EHOSTUNREACH 104.16.27.35:443 suggests that you have a networking problem. I was able to download the file mentioned there, so it woudl appear that you’re trying to get a file that exists.