Which of these three Certs will give me the most bang for my buck?

If you don't mind me asking, do you know what your true goal is?

To me, I see it as a three-way fork and so I'd recommend getting the certification that will best enable you to do what you want to do year over year because the motivation should be about you first. No matter what you choose, each is very valuable to employers in their own way.

1. You can continue to expand SM role.
   • Depending on organization and systems within, there are Chief Scrum Master positions, or Lead Scrum Masters etc. They essentially train and align Scrum Masters or service multiple teams. The other route is obtaining additional influence which extends your impact as a servant leader.
     
      
2. Agile Coaches typically have a broader horizon. Focusing on organizational changes and teaching strategy decision making by applying Agile Values and Principles first, for example.
   • If you were an Agile Coach, what would you want to be doing?
     
      
3. Keeping in mind there is no hierarchy between SM and PO, if you want to go into a PO role, than none of those certs will be as helpful as something else for PO's, and I would instead focus on that route entirely.
   • Why do you want to be a PO? Do you enjoy more project management and being the customer/stakeholder proxy for your team?

I am extremely good at being able to identify weaknesses in teams and bottlenecks / issues that prevent us from being successful. I'm also a big guy that tends to command a lot of presence simply by being in the room, so I am very good at being assertive, I don't back down from conflict and almost enjoy it, so long as it's constructive.

I also seem to do very well with reporting and data analysis. I learned how to use Team Foundation Server and JIRA completely on my own through trial and error, and now I'm pretty handy with both systems, so naturally backlog management and reporting just fits well into what I do.

When I found out there was a role where my job was to identify and track down ways of removing those problems, along with being the one who helps enable others to do their jobs better, and producing reports to management for greater transparency, it seemed like a dream come true.

Having worked as a scrum master, I've come to find out it's not really like that. You can identify and point out the problems within the teams / organizations all day, but if you're not supported by management / the business, you're not going to be effective, and I've found most of the problems in my last three jobs were because of management, and not because of the scrum teams alignment with scrum or agile principals.

I've found that within a few months, I can have a team up and running and starting to become self-organized, but then inevitably the impediments start mounting, and they aren't removed. Teams complain about the same problems again and again, and management pretty much just turns it around on them, well, what are you going to do about it?

Personally, I don't want anything to do with management, I find most people managers to be very ineffective and kind of useless, they're also usually worked to death and handled problems that are unsolvable themselves, and of course, they take the blunt of the blame for it anyway.

I would like to remain an individual contributor / consultant. My dream job would be working remote providing consulting for organizations that need help with transitioning into agile and helping them get it all set up. From what I've seen when I went through the two transformation processes with my last two companies, this is usually covered by Agile Coaches that are employed by a larger organization as consultants. So, I assume being an agile coach would be like this.

I also know Agile Coaches get paid almost twice what Scrum Masters get paid, considering I'm already getting paid above the median and I'm only a 2 year Scrum Master, I'm not seeing any real progression there, remaining a scrum master. Am I mistaken?

Don't get me wrong, it's not all about the money, and I have no real desire to be the one that comes into a company and has to completely redesign their dev ops processes / technology stack, which seems to be what a lot of companies are looking for, I don't even know how I would go about learning all the technologies / what systems are good for what etc to even be able to do that while not using the systems myself, seems like someone elses job entirely.

Hopefully that helps answer your questions, sorry if it's a bit rambled, I haven't been sleeping much lately.

Based on what you said, you don't need other certifications for employers to see your "more" valuable than ever. IMO, these certifications should not be the sole basis of getting specific role (especially higher ones). 

I've seen others who have tons of certifications and yet cannot answer simple scenario interview questions.