iPhone 17 Pro Max battery draining too fast

• First look at the battery usage stats on your phone and see if any specific application is running some weird background task that is draining your battery.
• Another option is possibly considering where you are and if reception on your phone is not great maybe your phone is constantly trying to connect to service. Try to reset network settings or even before that turn off 5G reception. See how the phone does with just 4G enabled.
• Next is back up and factory reset.

If after all that nothing improves its time to either call Apple directly, report the bug at apple feedback, if its a software issue.

Do NOT go to bed without putting it on charge!!

Most of the housekeeping and photo curation is done overnight, on wifi, on charge.

haven't experienced anything in that direction with my 17 pro (non max)

but when I go to bed, i place it on the wireless charger together with the watch, so nightly shenanigans would not be a thing for me.