I see! Thank you for the response.
After Years can be problematic on some devices because it uses a different engine than most of the fVNs out here (it's RPG Maker, rather than RenPy). RPG Maker is known for not-so great optimalization on mobile devices, because this engine heavily relies on a single CPU core performance (long story short, it's more PC friendly). To add the salt to the injury, I also decided to make the game in a high resoution of 1920x1080 px, which can also take a quite a hit on the performance. Sadly, I've realized about it way too late, and now, it would require a massive amount of work to make changes in this regard (scaling every picture that shows up in every scene, relocation all the game menus etc).
So yeah, to summarize - your device is by all means powerful enough to run a simple game like this - the real problem is the engine itself, and my mistake to not code the core script of the game with the mobile platform in mind (I simply wasn't aware how big Android user base is here on itch.io). I just hope that the low framerate won't discourage you from reading the novel - the game doesn't feature any "quick time actions", so you shouldn't experience any more unconviniences along the way.