My phone has been acting weird

so this all started about a week ago, I deleted and app because it kept crashing, so I went to redownload it in the App Store and the App Store told me “open” like it was still downloaded but didn’t work. I looked this up and said there was no fix that I had to factory reset. So I did, and so I started my phone back up, filled everything out and kept saying my back up failed but at the same time it worked and I got everything back. And now my phones really buggy every time I power it completely off and turn it back on it goes back to the welcome screen and makes me fill everything out again, also my App Store isn’t working, I’m able to redownload apps that existed before but will not let me download new apps. I’m not sure what to do. (Sorry this is a lot but I went into detail so you understand the problem.)