No push notifications on iPhone 7, iOS 15.8.3
I have an iPhone 7 with the updated iOS 15.8.3. I've noticed for weeks now that I don't receive push notifications until I open said app. I have done everything expected by making sure the notification settings of each app is turned on and also making sure dnd is off. I even reset notifications settings and that was a huge mistake as the problem still persists. I work with my phone but being able to receive notifications until I open the app is so inconvenient for me. I can't answer WhatsApp calls if the app is not currently launched, neither will I receive messages. Same thing with my mail, X, WhatsApp, TikTok, IG and every single app on my phone. To add to the fire, apps relaunch every time. For example, if I minimise an app, the app will relaunch when I want open it again.
What can I do? Should I reset my phone? Please advise me.
iPhone 7, iOS 15