Battery draining on MacBook Pro M4 Max with original charger

...draining battery while plugged in during heavy use.

Before useful Apple Knowledge Base articles were dumbed down before the Altar of Minimalist Design, Apple had an excellent and detailed battery article. Part of it explained that, when resource demand was high, a laptop Mac could draw power from BOTH the battery and wall power. I can't say if that is still the case today, but your evidence suggests it is. If this does not happen with low-demand tasks like word processing or checking Mail, that further intimates what is at play

Your energy chart shows Arena as practically, well, off the charts. High demand can include using an external monitor. Is that the case here?

Your computer performs best when connected to AC power, such as the power adapter. It can use the full output of the Power Adapter AND when doing especially challenging work could also freely "borrow" power from the battery. In some cases, even with the power adapter connected, the charged state may decline during very stressful work.

You appear to be doing work so challenging, it is using all available power adapter power, AND draining the battery at the same time.

¿Are you using the MagSafe cable for charging, or a USB-C cable?