When things are hard, it's often because either a) it's new, or b) because we're trying the 'wrong' way.
When something is hard and you can't manage to get the desired result no matter how hard you try, consider that rather than to keep working 'hard', you just try something different.
I know you haven't (and couldn't, on this forum) encapsulated the breadth of all of the things you've tried to overcome this lack of meaning that you've been experiencing throughout your life. But, and please forgive me if I'm oversimplifying your search, it seems pretty clear that you've been looking in the wrong places. Trying something different doesn't necessarily mean trying a different activity, or finding a new thrill, or a new drug, or anything like that. Put simply, it means try doing something that you wouldn't otherwise do.
When you say that the people around you hate it, that's what I'm getting at when I say, 'Can you imagine what it's like being on the other side of you?' Are you giving the people close to you the access and information they need to help you? Do they know you need their care? Do they know what things they do that give you energy, and what things they do for you that are demotivating and de-energizing? Simply giving them access to 'where you're at' can do a lot to empower them to help you. You can't get through this alone. You need to do everything you can to let them know that you're working on it and that they can help.
When you say that 'everyone else seems fine', that's a symptom of the lack of authentic connections in your life. If you're like most of the people on this forum, it's possible you spend a likely unhealthy amount of time working. That makes it crucially important that you have some professional relationships that can help fuel you to do the best work you can do (for the sake of your own business, your own sanity, and just generally making the world a better place by being easy to work with), and to get through the business of being a human being within the constraints of our economy. I don't know what business you're in, but I would be shocked if you couldn't improve it by being better connected to the people you're working with.
Whatever is stopping you from improving those connections, whether it's introversion, a sense of superiority, or simply being a low-friction provider of a minimal interaction service, just be aware that there are steps that you can take to make those connections stronger. There is not nothing you can do.
The fact that happiness comes from the inside is so easily written off by so many people is a persistent and vexing concern. Think of how much you contain, honestly. Within you is all of the pain and all of the joy of every Russian novel, every bit of the dazzling, puzzling, frustrating and ecstatic complexity of every single film, poem, painting, song, etc, ever made. The degree of difference between you and me and every other human being is infinitesimally small if you zoom out just a little bit. So, if someone else is able to apply that idea that happiness originates from within, so can you. I hate myself for writing things that contrived, but it's true. For what it's worth, you may have to take someone at their word that they were able to build happiness just with what was contained within them. Trust it. It's true. Set aside the practical dilemma of working it out in steps that can be described to fit your life, and understand that it's possible.
You mention having a dozen therapists. That sucks to go through that many therapists and not find 'the one', but please keep searching. It's the same with mentors. The compounding problem of trying to attain happiness and to have massive amounts of real effort turn up little reward is a huge and understandably discouraging one.
Despite the absurd and self-aggrandizing length of this reply, I have no answers and no wisdom that couldn't be more succinctly expressed through common idioms. The only thing I can offer is my own experience, and to vouch for the experience of some people I know that were able to slough off the feeling of torpor and malaise that can set in when hopelessness comes easier than hope.
Your Rodney Dangerfield example is well appreciated. The best comedians give us the pain of the world wrapped in a bow. I have found that in my own life, I get both much happier, and also experience much more sadness and even depression as I open more and deeper connections with other people, and with the world at large. In general, you just feel more. That is one of the beautiful (and obvious) things about connecting with others... you get to feel more.
The 'road' that I mentioned sharing with you was probably a bit presumptuous on my part... the road that I was talking about was basically my own history of trying to obfuscate my needs and feelings with more-than-casual drug and alcohol use, believing that the reason 'things' weren't 'happening' had mostly to do with people/influences/circumstances/other factors outside my control, which led to blame and avoidance and some bad stuff that comes along with those things.
Your example comparing the accumulation of experiences/memories with saving Polaroids is concerning because, sure, collecting Polaroids is a bit boring if they're all the same picture, but ideally they shouldn't be. But anyway the analogy doesn't really work, because the important factor is not that they 'happened', but instead that they accumulate, which leads to deeper connections, new connections, etc.
Sorry in advance for the ridiculous length of this post.