You can also easily disable physical cpu cores on bios level. Indeed this seems to reduce energy consumption read out (or estimated) by powertop. Just for fun I disabled 3 of 4 cores at the moment writing this. Running Fedora 35 on one core on an i7 1185G7 with 64GB. It does well on text processing and internet browsing as far as my spontaneous 2 hours experiment goes.
Don’t remember if this possibility was already mentioned.
PS: Being actively working on this machine Gnome and powertop are showing 6h left at 55% battery. Not too bad.