Go into the shortcuts app and create a shortcuts that turn off wifi when you leave areas where you use it and turn it back on when you return -- this will prevent the wifi radio from searching for APs constantly. Go into settings and check all your apps for background refresh -- there are probably a bunch that don't need to be constantly for new content when you aren't using them. Switch to Brave Browser instead of Safari -- the built in ad blocking will save CPU cycles on websites. With all of these set you can probably get another ~1hr or maybe ~2 if you have some egregious apps refreshing and a whole lot of APs you can't log into that keep coming in and out of range.
