There’s an intel-microcode Debian package that you might want to try and see if that makes any diffference. You might try the GNOME Power Manager to do some historical charting to see if you can spot anything going on along with htop or something like that.
FWIW, running Arch w/ 5.18.16 on a 1260P, I’ve had no issues with unexpected power usage, idle power consumption, or with system responsiveness so far.
Update: one more thing to check out if you’re CPU responsiveness is wonky: Linux battery life tuning - #204 by Michael_Wu