How do I fix a volume button on my iPhone that isn’t working properly?

How do I fix a volume button on my iPhone that isn’t working properly?
I’ve been having trouble with the volume button on my iPhone recently. It used to work perfectly, but now, no matter how many times I press it, there’s no response. I’m unsure whether it’s a hardware issue or something related to the software. It’s incredibly frustrating because adjusting the volume is something I do quite often, especially when I’m watching videos or listening to music. I’ve tried pressing the button harder, but that doesn’t seem to help either. Also, I’m concerned that opening the phone to check might cause more problems or void any warranty I have left. I need to figure out the steps to determine what’s causing the issue and find a way to fix it without causing any additional damage.