Reskinn flutter source code app & Build web version of the app ( all 3 synced)

I want to create a « classified ads project app+website « I found an app that i like ( this is the app link in codecanyon to check : [login to view URL] ) I bought this source code from code canyon But the problem it this gives only apps ( ios+android ) ! What i want you to do is to make the reskinning of the app ( logo, color, admob codes edit, firebase analytics integration, package name update , push notifications update, backend server installation.. etc ) so the apps will be ready to upload to the appstore and playstore ! And i want a web app that looks great in phone and laptop and all these 3 should be synced together Ps: the 3 apps ( ios, android and website) should have the same backend ! If i do an edit ( like categories or locations or something) it will be done on apps and also on the website