There’s a separate discussion on this: Mention kill switch leaks caused by OS limitations - #4 by ignoramous
In the “shared responsibility” model that most OSes operate in, the VPN provider’s responsibility is to make sure its clients are compatible with OS-provided or makes use of OS-assisted “killswitches”. Whether an OS itself “leaks traffic” despite the “killswitch” is not a problem the client can solve.
To give you an analogy, if an OS provides a “keystore” for an encrypted notetaking app to securely store its secret keys, it is prudent to demand that the app use it. Whether the OS’ “keystore” is backed by a tamper-resistant hardware security module (HSM) or not is secondary. A considerate notetaking app will however caution its user about the missing HSM.
money I’m spending on VPN and the inconveniences that come with it serve no purpose
If your ISP told you that they sell information about you, then using a proxy makes sense.
ISPs may however extract browsing profile from IPs you visit & from DPI (deep packet inspection), if need be even if one uses encrypted DNS; but there’s costs associated with DPI; especially with the ungodly amount of traffic that flow through larger ISPs. ISPs usually collect “flow logs”, from what I know, only in compliance of government mandates … which, VPNs might also be subject to as the EU e-Evidence Regulation notes above.
Some argue VPNs provide KYC-less accounts & payments; but when your devices connect to the public VPN provider’s servers, your IP is exposed to them anyway (an IP provided to you by your ISP who has done its KYC); so there’s not really that much to rely on & probably the reason why PG recommends Tor + Quebes / Whonix for those usecases. That said, this a discussion for a different thread.
Are you referring to a single “switch” that can be flipped on and off? If not, Linux-based OSes should let users control if all Internet-bound must flow through a VPN tunnel or be dropped, if not.
And what’s guaranteeing that the guest VM will not leak? It is the host. But you’re just now arguing that hosts like Linux do not provide “killswitches”…
Depends on the Android flavour. GrapheneOS, for instance, tries very hard to not “leak”, but Android has a security model in which privileged components are well… privileged. In that model, no unprivileged app (all user installed apps) are supposed to be able to “leak traffic” outside the VPN when Android’s “killswitch” (called the “VPN Lockdown mode”) is turned on. The catch with Android is though, the VPN apps must be compatible with the “killswitch” (ex: recently, hardening the ‘VPN Lockdown mode’ made a few popular public VPN provider apps non-functional on GrapheneOS).