Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.
When I bought my Supermicro X9SCA-F (also C204) and added a PCI-E graphics card, it also disabled the on-board video. There was no BIOS setting to override. Updating the BIOS to the most recent that was only 6 days old did offer that option.
So updating the BIOS is something I'd definitely advice.
DD-WRT can handle VLAN's, so a new switch isn't necessary. ESXi has no problems with multiple VLAN's on a single NIC, just configure the VLAN ID on the virtual network the VLAN's in DD-WRT. Then add routing rules to allow traffic between them.
(I tried this on a WRT54g, but DD-WRT became...