Hi @Stephen_Lee1,
You’ll need to enter developer mode to change the DPI. It’s something like this:
Step 1. Go to *Settings > About Phone and scroll down and find ‘Build Number’. You need to tap on the ‘Build Number’ 5 to 6 times continuously.
Open Settings > System > Developer Options. Under the Developer Option, select the option ‘Smallest Width’
Step 3. Under the ‘Smallest Width’ you will find the default DPI value of your device. Take note of the default value so you can restore if necessary.