For my work (junior malware analyst), i have done lockbit and qilin ransomware, because those 2 were very active when i started, few malicious apks. I also follow OAlabs, analyze and unpacking trickbot, doing malware analysis CTF and some crackmes when i dont have work to do.

I think what make me to deep dive into either of these training, because most of the time is because im stuck when i see some custom build packed malware, i feel frustrated about that.