My experience, as someone who's had internal promotions multiple times in my career at different companies, is that the only point here that's actually true is #6 about visibility, but that the author's take on visibility is a bit too narrow. Getting promoted is mostly about three things as an engineer:

1. Execute with excellence.

2. Establish a positive reputation, preferably as a subject matter expert

3. Align yourself to the direction of your business unit or the company.

In pretty much that priority order, actually. Whether you have a formal review process, quarterly goals and KPIs, take on duties off the HR-approved job description of the next level up, et al, none of that matters.

Visibility is all about #2. Being the engineer that sits in the dark corner hacking away and nobody even knows you're in the office (if you've ever had the lights turn off while you're still at work because someone else thought they were the last one out of the office, this is probably you) is not going to get you promoted. I am an introvert, and I will tell you directly that you do not need to be gregarious, charming, and a social butterfly to get visibility, nor do you need to go into 1:1s with your boss and brag for 20 minutes every month.

Visibility is as simple as:

1. Say hello to people at work when you come into the office.

2. Remember (or write down) people's names and what they do, understand the organizational chart of your company.

3. When someone asks you a question, answer honestly, including "I don't know." Use these questions as an opportunity to grow your knowledge.

4. If you find an area where there are a lot of questions and you consistently know the answers, lean in and be willing to answer those questions.

Doing this establishes a positive reputation (or at least a neutral one) and sets you up to be considered a subject matter expert on whatever niche you find yourself fielding questions about the most, which may not even be your specific job duties.

If you're consistently executing your job duties at above baseline standards and your coworkers across teams and departments think positively of you and consider you an expert on some topic, you'll find internal promotion comes relatively easily even if you don't have any formal review or KPI process.

Finally, and this is a big one. You have to ask for the promotion. Do not expect anyone to just randomly swoop down and promote you. It does happen, sometimes, but generally you have to advocate for yourself. In really well structured companies it as easy as asking your boss and they take care of the rest, but the reality is most people don't have great managers or exist in a well structured organization. So figure out who to talk to, and ask them.

I don't touch as much on #3 at the top because even if you're doing maintenance work on a legacy system nobody cares about, if you can become the hero to whatever department uses that system as their SME or be known positively as an SME on other things and are willing to answer questions outside your strict job duties about it, you can get promoted. It makes it vastly easier if you're working on something where your day-to-day aligns with the company's direction and vision, but it's not a requirement.