Hello there serhatonn,
Thanks for participating in the Apple Support Communities.
With swiping right while viewing notifications within iOS 15, this will take you to your Today View where you can have widgets for easy access to information so this isn't an option. Now you can tap the notification to open it directly in the app to view, as well as additional features listed below. To find more information, check out this resource: Use notifications on your iPhone, iPad, and iPod touch
• Tap a single notification to open the app that it's from.
• Tap a group of notifications to view all recent notifications from that app.
• Swipe left over a notification to manage alerts for that app, or clear the notification.
• Touch and hold a notification to view the notification and perform quick actions if the app offers them.
While we know that isn't the answer you're looking for, we hope the information is able to help with using and viewing your notifications with iOS 15.
Have a great day!