@phon3Xx Hi, what are your phone specs (make, model, more details)? From my perception, Android’s burn a lot of battery percent when they can’t get idle with the network adapters, e.g. you have one (or even more) app(s) around which hold up a constant TCP connection. This will cause your WiFi/3G adapter to stay awake and consume battery. How much it is strongly depends on which hardware you have. Some manufacturers for example use DTIM, and, if supported by the WiFi AP, it can help to allow the adapter go to sleep and wake up every X-th beacon. I’m also a lot “battery aware” with my Android 10 Xiaomi mi 8 phone. So I’ve disabled every connection method except local discovery, forwarded a port for Syncthing to communicate on my router and pointed the phone with static address to it. I never loose much percent when Syncthing is idle. Furthermore, I’ve set “Sync every hour for 5 minutes” and together with the WiFi AP max. bandwidth of around 400 MBit/sec. it catches up fast transferring new pictures over when I return home. I hope the generic info helps you a bit, but I don’t know your phone and firmware.
EDIT: Now looking a little bit closer at your screenshots. Do you have VPN on most of the time?
Screenshots of my config: