It isn't a single button press. Right-click -> inspect -> Security -> View Certificate. Although I have to agree opening a new browser for checking a certificate is hilarious.
F12 > View Certificate
well at least if you have had selected Security in the dev tools last
On macOS, it's the "intuitive" command + option + i , which I can never remember (and then you still have to click on the stupid security tab, which is hidden if you don't have enough horizontal space on the dev tool frame)
It is much worse than the previously convenient click-on-lock-icon -> view certificate. Even on windows, F12 is usually a Fn key, so I have to select Fn+F12 which I never knew till the GP pointed it out to me.