DNSMASQ_WARN for Max Concurrent Queries (max is 150) when using VPN or when using Pi-Hole as local network DNS with 35+ devices

My bad - you should run that command for your tailscale0 client IP address 100.66.218.18. I've edited my previous post accordingly.

So you are running Tailscale on your machine hosting Pi-hole as well as on some network clients, and clients are

The vast majority of DNS activity (over 90%) on your Pi-hole at 192.168.1.186 is caused by that client IP of your tailscale0 interface, which matches your observation of those max concurrent warnings appearing since you introduced Tailscale:

At the time you were producing the logs, were you traveling?
How many of your clients do use Tailscale?