Thank's for the quick response.
In my main pc (Ubuntu 22.04) I also use a rtl8125 network card (mainboard integrated) with ASPM enabled and never had a single connection drop or a reduction in transmission speed.
Currently Intel 2.5Gbit/s NICs (i225 & i226) probably suffer from a hardware defect which causes connection dropouts or complete connection loss. i225 NIC (2019) suffered first from the problem and Intel couldn't fix them with the release of the i226 NIC (2022).
So I wouldn't recommend anyone to buy them right now until a new hardware revision is released which fixes the bug.