In the west we tend to think of meditation as just the specific type of mindfulness practice that happened to catch on here, but there's really a whole plethora of meditative practices and traditions and different practices will resonate with different people. Its like how there's various different exercises and certain people might resonate with weightlifting while others resonate with calisthenics. Different practices are also meant to create a different effect.
Respects to you for being able to stick with meditation for that long without seeing a result, perhaps the plain mindfulness didn't do much for you since you already had a mentality that was capable in the way it would've helped.
If you were mainly focused on that one app though, if you have any remaining curiosity / patience for this what I'd suggest is experimenting with all sorts of practices for a short period of time each and just see if you feel particularly pulled to any of them. They all are "meditative" and involve specific ways of directing your attention/awareness/consciousness, they're all different paths to the same place, and I believe that different people are meant to take different paths.
Here's some areas you can look into and what you might be able to receive from it:
- There's contemplative practices of reflecting inward not to notice thoughts but to notice that which is doing the noticing. It's trying to seek out your true nature by taking the argument of "I can notice my thoughts therefore they are not me" further than that to "I can notice the noticing of thoughts too, so I'm not that either, so what am I?". The app "Waking Up" has some guided stuff in this area. Aside from simply an exercise in curiosity, there's a difference in how you move through the world and feel moved by the world as your understanding of what "you" are changes, just like how understanding that you are not your thoughts can be a radical change for someone. Advaita Vedanta is a whole field of philosophical inquiry around this type of thing if you're more attracted to that logical side.
- There's all sorts of breathing practices that can calm you or energize you or bring about all sorts of subtle changes that are really hard to put into words.
- There's chakra-based practices which rather than having to entertain chakras as a real thing you can interpret as just "this is a practice that is meant to produce a specific type of effect around what the chakra represents". You can think of them as categories of practices like exercising different muscle groups. Whether they work in the way they're described or not who knows, it's something you can just experiment with.
- There's practices that help with restfulness and sleep like Yoga Nidra, where it genuinely (scientifically proven, some people call it NSDR) can bring similar benefits to sleep
- There's the whole space of Yoga and Tai Chi if you want something more physical or flowy
So perhaps "the whole thing is just... nothing" is true for "the whole of what you tried for you", but the _real_ whole is much much more than just that.
Though in your position I'd be far too lazy to try these lol, I'm lucky in that starting off with the app _did_ feel like it produced a notable mental benefit so I had the reinforcement loop to keep exploring.