Is there a way to disable Face ID on my iPhone?

Settings>FaceID and Passcode>Use FaceID. Turn it off for the things you don't want it used for.

I have no idea what a "digital gate key" is.

Alejohh wrote:

Thank you I was not able to find it and would be another thing to worry about when we travel and think that someone is going to search our phone.

The advice given in the U.S. is to avoid using biometrics if you think your phone might be seized by law enforcement. Although it's not completely settled law, there is some precedent that law enforcement cannot force you to give up a passcode but they are allowed to force you to use the biometrics. Where you live or where you travel may be different.

The advice I have read for travel also says to keep as little as possible on your phone when you travel.

Alejohh wrote:

any other way to open an iPhone that will not be a violation of our rights.

I don't know what you mean by that.

Like some one using ur thumb print for example.

You can't use a thumb print on an iPhone that supports TouchID.

Many governments have issues recommendations to travelers visiting the US now to not take any smart devices, laptops, etc. with them at all due to the current environment.

US Citizens can refuse to allow their devices to be searched or examined. If you are not a US citizen, that is not an option for you.

If you refuse a request to unlock/search your electronic devices, they can be seized and you can be denied entry or worse.