Basically the P CPUs are much faster than U in previous generations but are also much more power hungry. The battery life is noticably shorter on laptops with a CPU like i5-1240P. And they produce a LOT of heat. I think one CPU option for framework laptop is i5-1240P.
https://www.notebookcheck.net/Core-i5-beats-Core-i7-Alder-La...
https://wccftech.com/intel-alder-lake-desktop-cpus-more-powe...
Basically the P CPUs are much faster than U in previous generations but are also much more power hungry. The battery life is noticably shorter on laptops with a CPU like i5-1240P. And they produce a LOT of heat. I think one CPU option for framework laptop is i5-1240P.