I think you're kind of mythologizing both FAANGs and Leetcode here. Leetcode won't get you further than doing amazing work and making your co-workers and colleagues happy. The OP is about how to get serious upgrades in the work you do. Leetcode is a thing that gets you in the door.

Likewise, FAANGs are not in every case "beautiful environments with amazing people dedicated to the craft of engineering." The most toxic person I ever met in my life spent years at Google, and he was not an impressive engineer by any stretch of the imagination. Amazon, Microsoft, and to a lesser extent Netflix are all notorious for having Squid Game cultures where everybody knows somebody will get fired soon and they're working hard to make sure it's not them.

Also, this is just false:

Pure programmers are just low value cogs in an assembly line, and being a great programmer only makes you a slightly better low value cog because it won’t be recognized.

I'm not saying it isn't true at any company. But as a statement about the overall industry, it's false. Great architectural decisions can add substantial amounts to a company's bottom line.

Likewise, this feels very naive to me personally:

What is the track for promotion at most companies - being a better programmer or learning project management and becoming a manager/lead who only spends 10% of their day coding?

Principal engineer can be an astonishingly lucrative role.