Win 11 Guest has Insanely slow Internet Speed

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Win 10 host, Win 11 guest.
- I've tried everything on this Vbox forum thread except for the Tuning TCP/IP Buffers for NAT, since I'm not using a NAT connection.
- Host has a wired connection with gig internet (900+ Mbps on speedtest).
- Guest has never gotten above 90 Mbps.
- Guest is using a bridged adapter to the host with a paravirtualized network adapter from Red Hat, using the latest stable drivers from virtio-win/virtio-win-pkg-scripts on GitHub.
- I'm using AMD-V.

Zipped log files are attached. They're large, so I had to break them into 3 zip folders to get under the attachment size limit. Hope somebody can figure out what's wrong with this, because I can't find any reason for my guest OS to have less than 10% the speed of my host.

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Update/bump:
I changed the network type to NAT so that I could try tuning the TCP/IP buffers. This made a slight difference, as the guest now runs at about 100Mbps consistently, but that's still not fast enough.
Currently, the buffers are set to 16000,1028,1028,1028,1028. The effects on my network speed between these settings and 16000,256,256,128,128 were negligible or nonexistent.

I don't know much of anything about networks, so my settings may be incredible inefficient. If this is the case, I'd appreciate some help figuring out what more efficient buffer values look like.

[fth0]

I can't find any reason for my guest OS to have less than 10% the speed of my host.

That's definitely less than expected. From my POV, significantly more than 50% should be achievable in a good setup. Before analyzing network details, I'd suggest to try the following changes for a test, to see if they influence the network throughput in any way:

On the host, uninstall all AV software (e.g. Malwarebytes) and see if it makes a difference.

In the VM configuration, disable System > Processor > Nested VT-x/AMD-V and see if it makes a difference.

In the VM configuration, set Network > Adapter 1 > Promiscuous Mode to Deny and see if it makes a difference.

Regarding the buffers, 1024 is the maximum value. You did mean 1024 when you wrote 1028, didn't you?

How did you measure the network throughput?

PS: Some general hints can be found in the VirtualBox User Manual in Improving Network Performance.

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On the host, uninstall all AV software (e.g. Malwarebytes) and see if it makes a difference.

In the VM configuration, disable System > Processor > Nested VT-x/AMD-V and see if it makes a difference.

In the VM configuration, set Network > Adapter 1 > Promiscuous Mode to Deny and see if it makes a difference.

Regarding the buffers, 1024 is the maximum value. You did mean 1024 when you wrote 1028, didn't you?

Uninstalled AV: no change.
Disabled Nested VT-x/AMD-V: no change

I can't change the settings for Promiscuous Mode if I'm attached to NAT. If I change to a Bridged Adapter, then I can change Promiscuous Mode, but doing that doesn't seem to increase the speed I get. If anything, I seem to have lost about 20 Mbps.

Regarding buffers: I did mean 1024. I shouldn't write these things so late at night.

I'm just using speedtest[dot]net. Nothing fancy.