Hi, and welcome to the Apple (user-to-user) Community!
Re: "Assistive touch toggle grey out" : " ... the toggle cannot turn on and I dont know why."
"My iPhone is 11. I know now is 16 already but tbh I dont have money to change yet."
Am no expert in this area, yet your post surely deserves some response.
See how you can: Enter and exit Assistive Access on iPhone - Apple Support
Many people still use iPhone 11. One of the main things is to keep the iPhone updated to the newest compatible iOS version available. Although the new iOS 18 can not be installed on iPhone 11, the latest iOS 17.7 version can be installed:
You may want to check if there is an update waiting to be installed:
Yoiu can look in Settings > General > Software Updates.
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If there is an update available: before you install the update::
You may want to back up your iPhone for safe-keeping of your data.
See how to: How to back up your iPhone, iPad, and iPod touch - Apple Support
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If no updates are available:
You may want to try re-starting your iPhone as that often restores order when something is not working as expected..
To restart iPhone 11:
FIRST: Press and hold either volume button and the side button until the power-off slider appears.
SECOND: Drag the slider, then wait 30 seconds for your device to turn off. If your device is frozen or unresponsive, force restart your device.
THIRD: To turn your device back on, press and hold the side button (on the right side of your iPhone) until you see the Apple logo.
(Above is from:: Restart your iPhone - Apple Support)
Please feel free to let us know if the situation improves, or if you still need more help:
or
If needed: You may want to contact Apple's Accessibility Support Team:
See: How to contact Apple for accessibility support - Apple Support
or
Apple's Accessibility Support Website (info. / support / contact options:
(NB: You can "Get Support" (online chat / phone / email etc.) from the link at the bottom of their website:). Accessibility Support - Official Apple Support
All the best :-)