can i use 65watts powerbrick for my iphone 14?

Yes.

Any Apple USB power adaptor can safely power any iPhone.

The actual “charger” is built-in to the phone itself and it will only draw as much power as it can safely use.

(not unlike how you can safely plug a 12w LED desk lamp into a 1,500w wall receptacle)

Charge your iPhone with the USB power adaptor of an iPad or Mac laptop – Apple Support (AU)

Can I use 65watts power brick or adapter in my iphone 14?

You can, but it really won't charge the phone any faster than a 20 watt adapter if that might be what you were looking for.