There is also bcl on fdroid, requires no dongle but root access, as it just changes some lines in a config file on the root partition.

Consider undervolting cpu and gpu and you will be able to get away with a leaner psu. I always do this and there really is no downside if you overclock the gpu a little to compensate for the undervolting. Your system will run cooler as well often stopping cpu/gpu from throttling down, so with a bit of luck you can even gain performance while saving on power. It depends on the cpu/gpu combo, but you can expect to save around 50 Watts under full load with both components properly undervoltet.

Here’s a very good guide for undervolting your gpu under windows, it’s meant for nvidia gpus but the process is very similar with amd gpu’s and/or under linux.

https://github.com/LunarPSD/NvidiaOverclocking/blob/main/Nvidia Overclocking.md