There is a setting in macOS power management that affects how the network adapter behaves during sleep. This setting can prevent the PIA app from reconnecting after the device wakes.
The Power Nap feature allows your Mac to perform background tasks while asleep, such as Time Machine backups and checking for email or iCloud updates. Because Power Nap keeps the network adapter active, your device may not disconnect from the network during sleep. As a result, the system does not trigger a network reconnection when the device wakes.
Disable Power Nap to allow the PIA app to follow its automation settings and reconnect after waking.
Note that Power Nap appears under both Battery and Power Adapter settings. Update the setting in both sections if needed.