Help choosing switch for on/off timed circuit
You may consider leaving the uC on all the time drawing uA of current only and use one (1) momentary switch to toggle a software controlled output OFF with X delay and ON with no delay.

If relay coil uses more than 10mA then drive with Nch "logic level" FET gate high to drive on low side of a relay coil for Positive Logic 1= ON.

Alternatively 2 momentary input switches or a latched SPST switch to ground with a pullup R can be used as input.

The power on state or 1st connection state should be defined  by design and all switches have contact debounce included by software filter or small Cap filter.







simulate this circuit &ndash; Schematic created using CircuitLab

Can't you just use sleep mode like everyone else?