Conclude publication of App (Flutter) for Android and IOS on Play Store and Apple App Store

I made an android app about flutter with dart. Unfortunately, having used a starting open source project, the google play store does not allow me to publish it as an update of the previous one. Same thing for the Apple App Store. The app simply, without any configuration, opens the website I own and allows navigation. So the purpose of the app is to simply open a website as if it were opening from a pc, with no ads added and no weird graphics. I just applied a standard splash page. What I ask is simply to insert the app on the google play store by updating the already present and older one and the publication of the app on the Apple App Store. There are two possible working methods, or simply fix the problems reported by google on the elements that it does not consider valid, or recreate the app simply using my code already present. I made the app in a day, so it's not too complex to build. The only tricky thing I can't do is post to the app stores. The indicative expiration date of the project is by the end of February but it can be concluded much earlier, being very basic. I'm just looking for someone expert in flutter and publishing apps on the stores :) I await your requests