Best System Monitoring tools

I’m interested in monitoring the processes running in a Linux system and determining when they are stuck/running endlessly very quickly.

Once I determine this, I also want to take on some actions (like dumping some debug info, restarting the process, etc..).

I know I can detect stuck processes using systemd, but unfortunately I wasn’t able to take action (where can I specify a script that I want to run when some process heartbeats are missed ?)