Laggy PC with Kernel 6.5 and AMD 5500U Lucienne

I am currently facing a problem with my Lenovo E15 laptop (AMD Ryzen 5500u "Lucienne" processor) and the kernel 6.5. (Xubuntu 22.04) Maybe three weeks ago, I noticed that my computer was having a laggy behaviour, applications were slow, Wi-Fi had hiccups where it took many seconds to respond, and of course internet surfing was awful. I was looking for a cause for all this, and I finally discovered that the CPU governors had changed. Before, I mainly used two governors on this computer: - Ondemand: most of the time I use this governor. It uses the good CPU clock for the need (1.4 GHz lowest) - powersave: when I play 2D games on the computer, I use this governor to reduce heating and vents as they were fluid at 1.4 GHz. And the new ones: - powersave: seems to behave like ondemand governor before but reduces the clock even more (0.4 GHz lowest) - performance: max out the CPU clock (4.0 GHz?) I thought that there was a bug in the kernel, so I decided to update it with mainline software, but the newest kernel (6.7.8 ?) has the same problem. When I switch back to 6.2 kernel (exactly 6.2.0-39.40~22.04.1), the problems disappear.  This is what I do for the moment, but Ubuntu 24.04 is pointing out and will I be able to keep 6.2 kernel with it? What other things I could test?