This is perhaps two issues.
1. The battery does not last very long. Perhaps this is because the display is kept on all the time displaying the time and etc.
2. When you plug it into USB and it is on, it does not seem to charge, so it eventually powers off. Then if you plug it back in, it will start charging.
1. As I understand it there is little to no powersaving features. I have not checked yet (but will try to remember to do) but my guess is that the cpu and gpu is running @full speed all the time. This along with screen on, wifi and modem on etc will ad up to maybe 2-3h of on screen time. Things will surely change in the future.
2. Make sure you use a good charger, 5V 3A is nice.
"- is there already a tool for overclocking it desperately?"
I suspect there are all kinds of permutations of chargers and OS installations that will make this hard to compare.
Nonetheless my limited 6p: pmOS/Plasma seems OK to me. With a USB dongle plugged in the charger (plain old, no PD) couldn't cope and the battery % was falling as I worked. Plugging the charger directly into PP gets % increasing. I have noticed pmOS/Plasma does screensave and eventually screenlock: during these phases battery charge increment is rapid.
So far I have been sitting with charger continually connected.
- ROCKPro64 v2.1 2GB, 16Gb eMMC for rootfs, SX8200Pro 512GB NVMe for /home, HDMI video & sound, Bluetooth keyboard & mouse. Arch (6.2 kernel, Openbox desktop) for general purpose daily PC.
- PinePhone Pro Explorer Edition, daily driver, rk2aw & U-boot on SPI, Arch/SXMO & Arch/phosh on eMMC
- PinePhone BraveHeart now v1.2b 3/32Gb, Tow-boot with Arch/SXMO on eMMC
possibly try using the cable that came with the phone if you are not already.
If it's plugged into a computer it will only get 5V 0.5A which is not enough to actually charge so it slowly discharges.