Is it safe to update iphone 14 plus to ios 17? recently many users faced green screen iss

It is safe to update at any time with the latest iOS if you have not done any of the following with your device.

if you have done one or more of the following Don'ts...

1. Don't Jailbreak: intentionally downloaded spurious software or unauthorized apps directly from the internet and installed them on your device or/and have Jailbroken. 
2. Don't share sensitive information pertaining to your device
3. Don't give in to Phishing
4. Don't plug in your device in Airports and Public places through third-party cables and trust the device. Beware of Juice Jacking. (Especially in India)
5. Don't leave your iPhone unlocked and unattended in public places like offices, schools, malls, etc.

Then goto Settings > General > Transfer or Reset iPhone, then tap Erase All Content and Settings. ... restore iPhone to factory settings, and ... Erase iPhone

Updating iOS on your iPhone should typically not alter the fundamental functionality of the device. It's possible that there were underlying issues before this update, which you might not have been aware of previously or might not have noticed.

In general, iOS updates are designed to enhance the user experience, improve security, and fix bugs, rather than introducing major disruptions to core features. The reported issue of the screen flickering and displaying a white screen after an update is likely caused by factors that are not explicitly mentioned in your post.

iOS updates primarily focus on improving system performance, introducing new features, fixing bugs, and enhancing security. They are designed to preserve your personal data, settings, and information intact.

During an iOS update, your device's operating system is upgraded, but your personal data, such as contacts, photos, messages, and other information, should remain unchanged. However, it's always a good practice to perform a backup of your device before any major update to ensure that your data is safely stored.

It's important to note that while an iOS update itself should not alter personal details, it's possible that certain features or settings may be adjusted or improved with the update. In such cases, you may need to review and adjust specific settings to match your preferences after the update.

Always make sure to read and understand the update details provided by Apple before proceeding with an iOS update, and follow best practices such as backing up your device to minimize any potential risks or complications.