I think you need to try and use Tor to see if it will connect. Download the latest Tor browser from this link. https://www.torproject.org/download/.
Install and start it for successful connection, after that you can follow these steps below.
Start Electrum and go to Tools>Network>Proxy
You will notice additional Tor related checkbox appeared named "Use Tor proxy at port xxxx"
Check that.
Go to Tools>Network>Server and make sure Server is selected automatically.
Connection should be established instantly.
https://www.reddit.com/r/Electrum/comments/cdle3h/electrum_wallet_not_connected_solution/
Or you should read this thread to see if it will help you, if you try the above and it did not work.
https://bitcointalk.org/index.php?topic=5415431.0
Install and start it for successful connection, after that you can follow these steps below.
Start Electrum and go to Tools>Network>Proxy
You will notice additional Tor related checkbox appeared named "Use Tor proxy at port xxxx"
Check that.
Go to Tools>Network>Server and make sure Server is selected automatically.
Connection should be established instantly.
https://www.reddit.com/r/Electrum/comments/cdle3h/electrum_wallet_not_connected_solution/
Or you should read this thread to see if it will help you, if you try the above and it did not work.
https://bitcointalk.org/index.php?topic=5415431.0
I tried the first method using Tor and I had no luck with my server or the public servers either.
I will try the second thing you listed though.