Unfortunately, the pcie_aspm=off did not help, but it seems that the bug might be resolved anyhow: In the bios there are the options "Linux" or "Windows 10" for suspend. When selecting "Windows 10" suspend is working again. With Kernel 6.0 also the "Linux" setting was working. I will do some more tests, but right now it seems that the "Windows 10" setting has resolved the problem. Thank you for looking into this!