Remember with Ethernet, the problem can always be the far end of the cable. If you've got another switch/router that you can use (or even just a different port), it's worth trying that to see if anything changes. Switches can sometimes disable a port if they see problems, or similar. It could also be some weird interaction between the I225-V and whatever is on the far end of the cable, so trying a different setup might change that. Unplugging and replugging the cable can sometimes reset that. I'm not really giving you a fix, just some things to try which may get you some more data points in the diagnosis process. Something else to remember is that 2.5G is relatively new, so you could try running it at 1G and see if that changes anything.
For what it's worth, I'm finding the I225-V on the Crosshair VIII Extreme to be stable connected at 2.5G into a ROG GT-AX6000, with driver 10.0.2.22 on WIndows 11 Pro.
Does it also occur on bios 1601 with bios all default settings(without OC) and Intel(R) I225 Gigabit Ethernet Driver V188.8.131.52 from our support site?
If yes, and you bought the motherboard recently, please consult the retailer first or send the motherboard to our RMA for further examination.
I'm having the same problem regarding lan dropouts on Win11 (fresh install, all upgrades). I've upgraded to the 2305 bios, all drivers are updated (as shown in armoury create app). I've also checked if the mobo was in the recall list but it's not.
Has anyone solved this issue?