If I was seriously concerned, did research, and all I could come up with were an article about security issues 10 years ago and a short list of CVEs with no scoring attached then yes, that would make me feel better. But I’m not claiming any piece of software is vulnerability free, and you aren’t making a good faith argument.

It isn’t clear to me what you have against Qubes as a platform, but I stand by my previous statement: Xen jailbreaks are not unheard of, but they are less frequent than KVM jailbreaks, partly due to the smaller attack surface.

KVM guest escapes won’t affect Qubes, which doesn’t use it. Qubes is built on Xen instead - the Linux dom0 is itself a containerized management instance. That’s not to say that Xen container escape vulnerabilities are unheard of, but it’s a smaller attack surface and they are less common.