Do I need a hub for a smart lock?

It depends on the connectivity. Built-in Wi-Fi locks (several Philips models, the Ultraloq Bolt SE, Schlage Encode) offer remote access with no hub, while Bluetooth and Zigbee/Thread locks like the Aqara U50 and U100 typically need an Apple Home hub, Aqara hub, or a Thread border router for remote control and full features. Reviewers repeatedly note that Aqara's cheaper locks lose remote functionality without the extra hardware.