If the standard 15 days is not enough for testing, there are official routes to follow:
If your 15 days are up but you aren't ready to buy a full license yet, the developer provides a legitimate path to keep going: Hitting a problem with your PaperCut implementation? Reset Trial Usb Redirector Technician Edition 2.3 2021
If you need to continue using the software professionally after the trial, you must purchase a license: If the standard 15 days is not enough