Hi Jukiii
welcome to the Apple (user-to-user) Community!
Re: "Side Button Double Click doesnt work (iOS 18)"
You can adjust accessibility settings for the side button (on an iPhone with Face ID)
or Home button (on other iPhone models).
See how to: Adjust settings for the side or Home button on iPhone - Apple Support
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Re: BTW - there is no Option in accessibilities for the side Button anymore, so I cant change the Click speed of it.
The article above says:
"Go to Settings > Accessibility, then tap Side Button (on an iPhone with Face ID)
or Home Button (on other iPhone models)
Set:
- Click Speed: Choose the speed required to double-click or triple-click the button—Default, Slow, or Slowest.
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Re: I‘d really Like to be able to use Apple Pay….
If you have the iPhone SE (3rd. gen) model:
Seems a fingerprint sensor is built into the Home button so you can use Touch ID.
How to: Identify your iPhone model - Apple Support
Apple support has an article on how to: Set up Apple Pay - Apple Support
Eg: The above article may guide you to:
"Verify your information with your bank or card issuer. They might ask you to provide more information or to download an app before approving your card for use with Apple Pay."
or
If you need more help with an accessibilty feature:
You may want to reach out to Apple's Accessibility Support Team:
How to contact Apple for accessibility support - Apple Support
or
For Apple Pay: contact the Apple Pay Support Team.
There is a "Get Support" link (phone or online-chat etc) at the bottom of their webpage.
Apple Pay - Official Apple Support
All the best :-)