Smart, the answer is yes, just keep in mind that it will be in total of 100 Mbps, unless your router is 1 Gbps.
And plug in from LAN port to LAN port is to avoid going through CPU processing(also avoid double NAT), so the cpu will be in powersave and only WiFi+LAN chipset are running most of the time.
It sound like the Ethernet adapter causing interference of the PCI-E processing, and yes, it can happen.
For example, my laptop because of louzy Qualcomm WiFi chipset, it wake up the CPU Package constantly and using 10 watt for nothing.
I had try to forcing it into powersave while nothing is transferred(found hidden registry value on inf), but it will buggy, and it is just like saving 1% instead of 99% using Intel WiFi chipset.
There is also same for the Qualcomm Ethernet, the solution is simple like yours, enable and disable again kick it back into power saving mode.
But now as I just leave it as enable, so it is no longer a issues.(how stupid I am, thinking disable might more power save)
Here is the Task Scheduler's task that I created and modified to disable then enable, just give you la.
You can also using Notepad to open it before import into Task Scheduler, just for safety la.
It is performing as below.
When logon into any user, it will using SYSTEM account, running netsh "interface set interface "Ethernet" DISABLED", netsh "interface set interface "Ethernet" ENABLE".
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And yes, the Ethernet chipset also buggy after I disable and enable by modifying those Offload task feature, so it is very buggy indeed.

Thanks for the task scheduler script! So far I haven't encountered this issue anymore since last week, I removed my custom IP address and DNS (use router to set DNS now) and it hasn't happened again. Though I am not sure if that was the actual course.