Unable to decline call by side key

This issue pertains to incoming calls only, not calls already in progress. When I receive an incoming call that I don’t want to answer, I miss the red button that used to end the call or send it to voicemail. The side button, which you all suggest, merely closes the screen without ending the call or sending it to voicemail. Additionally, the side button is inconveniently located and being hardware-based is impractical.

When I’m using my iPhone for other tasks, an incoming call takes over my phone until it stops ringing. I can’t stop the call and continue using my phone. Am I really expected to use the side button to close the screen and wait for the call to end on its own? Why is there no red button to end incoming calls anymore? It used to be there. Rebooting doesn’t help either. The red button only appears when I have earbuds connected.

I just want to dismiss incoming calls and continue using my phone without interruptions from spam calls. To clarify, I want to stop incoming calls and still use my phone. The side button does not achieve this; it only closes the screen. As a longtime Apple fan, I’m disappointed with the recent decline in product quality. Please provide a fix urgently! I’m using an iPhone 13 with the latest iOS as of this post.

please resolve it as soon as possible. Thank you