Periodic NIC issues (?) with Protectli Vault, Intel i226-V

[fornax]

I'm working on troubleshooting an issue that's been popping up irregularly since deploying OPNSense on a Protectli VP3210 (both new to me). The device is set up to perform all DHCP, DNS, firewall, and routing duties for the home network behind it.

Approximately every 1-7 days the network starts acting up. The symptoms aren't always consistent, but so far have tended to fall into one of three categories:

1. Something that looks like a DNS issue. Attempts to resolve an address will usually time out first try, but then succeed immediately a few seconds later. If I connect to the upstream router and use the same resolver, everything is normal.

2. DHCP will stop working for some/all devices.

3. An online game I play regularly has trouble connecting to the game servers.

Regardless of the symptom, the workaround that resolves it (temporarily) is the same. Go to Interfaces -> Settings, uncheck "Disable hardware checksum offload", Apply, recheck the box, Apply again. Everything immediately starts working as it should. (This is why I assume this is a NIC issue.)

Doing some research, I see that it's not uncommon for people to have issues with the Intel i226-V NICs, something I missed when I chose the hardware. Based on what I read I've been playing with various tunables, rebooting as necessary:

dev.igc.0.fc=0
dev.igc.1.fc=0
dev.igc.0.eee_control=0
dev.igc.1.eee_control=0
net.isr.bindthreads=1
net.isr.maxthreads=-1
net.isr.dispatch=deferred
net.inet.ip.intr_queue_maxlen=3000
hw.pci.enable_aspm=0

So far nothing has made a difference. The other thing that seems to be done commonly with these NICs is to upgrade the NVM firmware, which I'll try if I have to but that's a bit intimidating. Anyone have any other ideas before I go that route?