Here is a step-by-step guide on how you can quickly disable the website tinting feature in safari on your iPhone.
Step 1: Open the Settings app on your Apple iPhone or iPad.
Step 2: When the Settings application opens, tap on the “Safari” option from the list.
Step 3: Now, toggle the switch from ON to OFF for the “Allow Website Tinting” feature.

That’s it. changing the status of that toggle switch will disable the feature on your Apple iPhone or iPad, running the latest iOS 15 or iPadOS 15 or later versions.
For any reason, if you want to enable the feature, you can follow the same steps and toggle the switch again to enable it on your device.