The usual culprit should be the DNS filtering.
Either try different DNS providers to compare speeds, or you can use the system default DNS server.
Using the default DNS server usually solves all connectivity issues.
I have the same issue.
We use a corporate VPN for remote work in my Company and if I leave the DNS protection on, the VPN cannot establish connection.
So far the only solution is to temporarily turn off the DNS protection manually and connect to the VPN to do my work.
Some kind of ruleset for...