I'm afraid this thread is discussion of 10Gb Ethernet.
Looks like your issue is with 2.5Gb Ethernet. Please post a new thread for you issue.
Does it also occurs with Marvell Ethernet connection Driver V18.104.22.168 from our support site? How often does the issue occurs?
Please try the following steps:
1. use Marvell Ethernet connection Driver V22.214.171.124 from our support site to see if the slowing down and disconnecting issue still occurs.
2. disable "Recv Segment Coalescing (IPv4) and (IPv6 if needed)" in LAN adapter properties
3. if there are options like Energy-Efficient Ethernet, Power Saving Mode in device manager > network adapters(Marvell) > properties > advanced, please disable them to see if the issue persists.
i got tired of trying to fix this issue and asus is clueless, someone needs to start a class action on this.
i just went out and purchased a usb c network adapter and im not bothering to use this port.