MacBook M4 Pro battery discharging faster after update

Give the Mac at least a few weeks to settle down and adapt to your every day use routing.

Meanwhile, here is some of Apple's guidance regarding battery performance, health and management:

Batteries - Maximizing Performance - Apple Support

About battery health management in Mac laptops - Apple Support 

In a nutshell, to get the most from your battery:

• Let the OS and charging circuits manage the charging.

• Plug in when using the computer near available power.

• Use on battery when ac is unavailable or when you must be mobile.

• Don’t subject the computer and battery to extreme temperatures.

• Don’t allow the battery to regularly discharge deeply before plugging in. Yes, it may happen from time to time, just don't make it a habit.

• Don’t obsess over battery life and/or health.  

I understand.

It takes time for the OS to recognize and adapt the charging to your pattern of use. It can take many weeks depending on how often you use the Mac and in what fashion. If your use pattern changes or is interrupted then the amount of time it takes the OS to adapt the charging cycle will increase. The charging cycle may change at any time when your use pattern changes as well.

To increase the daily time you can get on a charge, you can enable the 'Low Power Mode' in System Settings... > Battery.

About Power Modes on your Mac - Apple Support

In the long run, the best way to ensure the greatest life of your battery is to plug in the Mac when you are close to a power outlet, and use the battery only when you must be mobile.