OpenBSD's track record is impressive but is it a significant target compared to Windows, MacOS, and Linux?
It is easy to say "only two bullets have ever penetrated my armor" when hardly anyone is shooting at you. I do not know if this is the case because I have never used OpenBSD and I do not know how widely it is used (headless servers, embedded devices, etc.).
You can read more about OBSD's security by going to https://openbsd.org then clicking the "Security" link near the top left.
ps: FreeBSD seems to have more users than OpenBSD, and NetBSD seems to have fewer users than OpenBSD.
Also I separate things by user account, so I don't do my general browsing as the same user that does my programming, which is again separate from bank access, which is separate from .... So the kernel is providing a lot of protections.
(And I usually browse without images and javascript, which is not OS-specific but a suggestion. Many things I use don't require it, and I can flip it on or configure it specifically for those that do.)