These are just my observations on how I prefer the sound of Tin Hifi T4. So, this is not a guide.
Anyways, I bought the Tin T4 back in 2019. I like the build and the clean sound. It always seemed too perfect. You cannot find any faults. But, to me, it's kinda boring, not much fun to listen to. Also, the soundstage is quite limited (ok for $70 though). So, I tinkered with the tips, cable and the source. Finally, this is how I use it -
For tips, Azla Xelastecs. It has wide bore and creates a shallow fit, which by nature expands the sound stage compared to spinfits and stock foam/silicone tips. The isolation is excellent, so you don't lose the bass even it being a shallow fit.
For cable, I use the ALO Smoky Litz cable. I'm also not a believer of cable changing the sound, But in this case, I'll have to admit, it does. Makes the T4 slightly less bright and a bit smoother. The problem with the stock cable was, whenever I connected with my laptop the hissing sound was unbearable. On top of that, that cable carries electricity to my ears giving me pinching sensation on my ears(maybe that's why the sound was harsher). This just shows not every cable are made the same. They do change your listening experience.
For source, I'll suggest any warm or smooth sounding source. As I mainly use them on the go. I use the Fiio Btr3k. It has a hint of warmth, and if you use Aptx HD or Flac, it's quite good.
Finally, I got Dolby Atmos for headphones in my laptop. If you enable this, the soundstage becomes quite acceptable for he T4s.
Well, these are my suggestions for making your Tin T4 sound better. You guys can suggest your preferred ways of listening to Ti Hifi T4s to me, I'll try them out.