The bottom line is that good flash photos are not easy, and a tiny on-camera flash is about the worst possible way to do things.
I'd like to think that I can at least do decent flash work, but my best efforts are using multiple stationary lights primarily with modifiers like umbrellas or softboxes, but also sometimes with more specialized ones like beauty dishes. If I do use on-camera, I like handle mount or otherwise on a flash bracket, and bounced whenever possible. If I have to do direct, lately my preferred set-up has been a Quantum Q Flash on a Stroboframe with the 2" reflector and diffusion disk, although that's just the "least bad" option that's easy to use(even though it's heavy and bulky).
For this photo, I'd have been tempted to use something off camera with as big of a diffuser as I could manage(umbrellas and such are easy, but I've made do with copy paper and the like before). If the camera the OP is using allows any sort of manual control over flash, I'd have cranked it down as much as possible just so that I could trigger an optical slave on the off camera flash(a lot of optical slaves will still work if you gel the on-camera with an IR filter, which keeps from adding significant light to the scene).
That's just me, though...
BTW, cell phone cameras are pretty impressive these days, especially on higher end phones. The one on my iPhone 14 often amazes me. I use dedicated interchangeable lens cameras because they give me more control and also because there's no getting around the sort of look that different sensor/film sizes give an image(plus when you get into things like autofocus tracking, it's hard to beat high end DSLRs or mirrorless cameras), but often times my phone gets me a pretty darn good result without me having to think about it.