iPad upgrading

I use a 6th generation iPad for digital drawing, however when I send my pngs of my finished works from my iPad to my iPhone 13 pro max, the difference in the colors is so noticeable, and it looks terrible knowing that what I make on my iPad isn't the actual colors showing up. Why could this be? Is it because my iPad is super old and outdated? Keep in mind my iPads storage is absolutely filled to the max and I haven’t updated the software since the past 2-3 updates. If I were to fix those issues would my iPad perform better? Should I start looking into upgrading?