It took me a bit to find the ticket you had with support, it was closed out a few weeks ago, but i did manage to find it. It looks like their assessment is correct, you’re experiencing a known issue involving 10th, 11th, and 12th gen Intel CPU’s with integrated graphics.
It’s not really a Zwift Specific issue, but there are a few things we have been able to do to correct the issue for a fair few members. There are still some that have the issue, like yourself. It has to do with how the Intel chipset processes the graphics.
The Zwift community has managed to find some workarounds for it, they don’t work for everyone but it’s worth looking into. everything from changing the height of your socks in game, to rolling back to previous graphic driver versions, along with how to guides for most of it.
The following forum threads seem to be the most thorough for the various workarounds if you’d like to check them out.