Intel Macs used a System Management (micro-) Controller to manage certain always-on functions like Main processor-clock speed regulation, power-button press detewction, Main Processor power-up and power-down, temperature sensor reading, fan speed regulation, power adapter and battery charge level, and setting the green or amber LED in the MagSafe connector (when present). These functions were controlled even when the computer was nominally OFF. Some Power was consumed when nominally powered off, but it was small enough to be considered negligible.
Apple-silicon Macs have moved most of these duties to one the low-power 'main' processors, and will consume some power even when nominally off. All those jobs still have to get done when nominally OFF.
It is possible that Apple may have changed what processor, and when, and how fast, and how much power is consumed, when the system is nominally OFF.
Since the nominally-Off power consumption level was never published, an increase in power consumption in a recent upgrade to MacOS is not likely to be considered a Bug. It it were identified as a Bug, the likely resolution would be to revise the documentation to reflect the actual use of power when nominally OFF.
Best advice is to NOT anguish over internal power consumption, charging and discharging. All that stuff is a job for a computer. When AC power is available, plug in your Mac.