Completing those courses was probably the most useful thing I did when prepping for interviews as part of a career change 6 years ago.
Don’t worry about formal qualifications. This is an industry where the largest and most successful companies were started by college dropouts. It’s still very young and things are changing faster than academia can keep up. A willingness to learn and relearn is critical.
My prep for big tech interviews basically boiled down to those algorithms classes, doing ~150 leetcode problems, slapping together a small junky android app, and perusing undergrad CS material on Wikipedia. To be honest, the first two are probably enough to get your foot in the door at the biggest companies.
The one major difference (it is a tendency, not absolute) between software devs who came from CS and those that changed careers into it is a deep passion for computers and how they work. Look at HN, there's a lot of talk about Lisp, Assembly, C etc. although few people actually need it for their jobs. Dealing with these things usually comes from a place of passion more than a place of necessity, and they do make you a better dev, too.
A book I can warmly recommend if you want to see how deep your own interests go is "Principles of Programming languages" by MacLennan. He takes a historical approach, explaining the design principles of programming languages by looking at historically game-changing programming languages that few people still use today. The exercises get progressively more complex, and the last exercise is to design and implement your own programming language, a task I haven't yet done myself.