No, you cannot use the app without enabling a screen lock on either iOS or Android. This is a necessary security feature to protect your funds and your data.
All traditional screen locks are supported, including patterns, pin codes, and passwords, as well as the biometric security features built into your phone, such as fingerprint and facial ID scanners.
NOTE: Turning off your screen lock after setting up the Valet will log you out of the app, and you will be prevented from logging back in until it is turned back on.