There are also third-party apps that can help you to insta zoom increase the size of Instagram profile picture. These apps often offer additional features such as saving profile pictures or downloading high-resolution images. Just search "Enlarge Instagram Profile Photo" in App Store or Google Play Store to find a suitable app.
If you don't have space on your device for extra app or don't want to install extra app, you can also use online tools to enlarge Instagram profile picture. There are various websites that offer this feature. Just upload the profile picture and the tool will enlarge it for you.