DFIR is broad enough that it's also worth thinking of specific subtopics to go after individually to make it feel like less of an information fire-hose. Depending on your needs, you can narrow the focus down to more immediately applicable topics and focus on their basics

That said, as @hacks4pancakes stated, @chrissanders88 has some good content on network and @hal_pomeranz has good stuff for Linux. @Antisy_Training has also been building out a good course catalog antisyphontraining.com/