iPhone 12 Pro battery issues

Right, so my first question got deleted (probably because it was about macOS Ventura but the topic was labelled under Monterey... sorry about that), but hopefully this one won't get deleted.

So, recently my iPhone's battery has been terrible. It was ok out of the box, but about a year and a half later, it is terrible. Sometimes it will not show it losing any percentage, but then when I pick it up again it loses a percent or two. It also seems to lose more battery overnight than it used to, and when I check to see what caused it, it says Siri for about an hour and then nothing.

It's a very frustrating issue, and it still loses battery even when I firmly power it off. Huh?! I understand losing a bit of battery, but iPhones are known for excellent standby battery, and mine just isn't that good at all. Currently, its maximum capacity is 93% relative to when it was new, so that could be one of, if not the main factors. I want to point out, however, that I do also have Low Power Mode turned on, yet that does not do anything.

Does anyone have a solution that at least helps me to save a tiny bit more battery? Any help would be greatly appreciated. Thanks! (I think that "Using iPhone" would be the correct topic for this, but I have no idea - it IS an issue when I am using my iPhone, so I guess so.)