It happened to me as well, except I couldn’t access specific domains for whatever reason, i.e. google, and judging from the comments you left, I decided to downgrade the version of Network Manager.
If you don’t have it, install the downgrade package:
sudo pacman -S downgrade
After that, downgrade the networkmanager package:
sudo downgrade networkmanager
Select any version prior to 1.36, I chose 1.34 and after that’s done, just restart the service:
sudo systemctl restart NetworkManager
Hope this helps at least someone, I’m not sure how to go about this if you’ve lost connection to the outside world. 