Hi,
generally the only answer to your question is: Buy a digital camera (DSLR, system camera etc) with the possibility to take pictures in RAW format and take your photos with it.
Here you can avoid technical problems which inevitably occur with smartphone photos due to the small sensor. Artifacts and image noise are typical here and these are intensified with too strong image processing.
Adobe Stock expects high quality images in terms of resolution, sharpness and image composition. Technically, a smartphone does not offer a good prerequisite here, and as far as image design is concerned, it would certainly be advisable to obtain comprehensive information in the https://helpx.adobe.com/stock/contributor/user-guide.html in order to be able to achieve better image results here and get them accepted.
Greets,
v.poth