Cloudflare has random ping timeouts or spikes to 300ms when switching from South or North India killing connectivity unless the router is power cycled. It took out smart devices which refused to connect or renew IPs after dns flush. Haven't been using Mullvad very much because of the same issue with wireguard. Sometime it works great with 10Gbps server but 1GBps server have poor performance for the same location.
Tried Quad9, NextDNS etc and even Secure DNS on Chrome,Android behaves exactly the same frequently. With Google, timeouts are reduced to once per day versus couple of disconnections especially during afternoon/evening/night.