This is a hard space to break into because it requires in depth knowledge of operating systems. I'd play around with volatility https://github.com/volatilityfoundation/volatility.

Next take a look at getting good with IDA, it's expensive but they have freeware versions you can use, it just won't do x64.

Start by specializing in only one OS, pick linux/mac/windows. It's a very niche space and requires a lot of expertise if you want it as a job.

If you're thinking long term I'd take a look at becoming a malware analyst as it will also help you pick up skills needed to go down the path you'd like.