* memory safety and exploitation (the "buffer overflow" section is about 20 years out of date, though super appropriate for a first course)
* the WebPKI/certificates thing
* messaging security and messaging cryptosystems,
* microarchitectural security and hardware side channels.
Multiple full courses on each of these subjects would bring you up to "practitioner" levels of expertise.
1- When this internet thing came out
2- When this covid thing came out
On the first era, here's a Java lecture from Stanford, if it's too basic for you, it still has historical value, iirc it's something like Java 6. And it also reinforces the basics.
https://www.youtube.com/watch?v=KkMDCCdjyW8&list=PLA70DBE71B...
It's a bit harder to follow along with online materials since you have to use the Internet Archive, and download older compilers or use options to target older versions, but it's all the more fun for it.
I kinda think the dark side is now pretty competitive, though.
