How do industrial researchers get access to online journals?

But I suppose normal industrial jobs (e.g. software engineer in Amazon) don't grant online subscription to journal (like, access to a network IP with subscription, just like many university accounts).

Some industry research labs do subscribe to digital libraries, though in my experience, not as many as a university. For example, in the industry research lab where I'm currently spending my summer, I can access the ACM digital library, but not Elsevier journals.

To access papers that are not available by subscription, researchers in industry usually try one of the methods described in the answers to these questions:

• What do you do when you find yourselves with an unreadable/inaccessible paper?
• Access to journals for individuals outside of an institution?
• Ways to get free and legal access to research papers as a researcher

It is often possible to get a library card from your university library. Someone will have to pay for it - presumably your employer - but I can't imagine that if access is essential to your work lack of access would be a longer term issue.

(Some schools also allow some form of access for alumni, usually at a discount over regular paying non-university members.)