What I have suggested here at home when wifi is available or in case charger is not available outside simply disable 5G ..mobile gonna latch on LTE+ for longer battery run ..That's my experience with M34 5G ..Hope this makes sense .

Wipe cache and restart do also reset APN settings..give a try

Turn off 5G and check battery drastic change and gave you more then 14-18 hours on LTE+

My battery backup more then 18 hours just disable 5G runs on LTE in case 5 G not required save heavy amount of battery  sharing 5G speed on my area Delhi JIO

Samsung M 34 5 g Serious issue on lags ..apps open close is lagging ..providing amoled screen with laggy performance is nor an customer support issue rather UI bugs needs ro be address or make lighter n faster UI