I recently started a SRE role at a large techish company (not exactly a tech company but hires lots of SWEs) so I might be biased from that experience. But adding on to #2, knowing how to navigate a Linux terminal. You don’t need to be a wizard but you should (at the very least) know the basics. If you can, you should also definitely take some classes on OS and computer networking. Knowledge of those subjects (especially networking) tends to be highly applicable in anything that touches the