Would love to see the PKGBUILD as I have no idea what you're talking about. Is it about PureVPN's software packaged as a PKGBUILD of your making?
Really depends on the DNS server configured, but in general anyone in your network, anyone with access to your router, anyone on the way to the ISP and the ISP itself. If you use different DNS servers than your ISP's, anyone on the way to that DNS server plus the DNS server operator. That's because DNS is unencrypted.
The picture changes if you use DNS-over-TLS or DNS-over-HTTPS, and if you're connected to a VPN server.
Depends on the software. All of AirVPN's software use Network Lock and change the DNS servers by default after connection so that no such leaks can occur. So whether you're leaking or not fully depends on the software, not on the OS.