Linuxcnc & the Raspberry Pi (4 & 5) Official Images Only!!!

There was a user having an issue with gmoccapy locking up, but this issue was related to zram, which was discussed earlier in this thread.
I've had my RPi 5 sitting there with Axis open connected to a "cobbled together" 7i92 and after a week and a half have only dropped one packet.
When I get a chance I'll look into the ethernet setup. For some basic advice, do not have a gateway nor DNS server entry for the NIC that the mesa card is connected to, it generates unwanted traffic on that interface.
TBH I'm not up on the meaning of the LEDs on the card you are using.
It maybe worth checking the manual and searching the forum for that answer.

RPI5 with a 7i96, and after some time I get a solid red INIT light on the mesa card, and obviously at that point have to reset the card to continue.

If the init light turns on when LinuxCNC is running, (with any Mesa Ethernet FPGA card)
it means you have a watchdog fault, likely because communications have been lost
for longer than the watchdog timeout setting. This is likely due to a network latency issue.
No reset is needed, though LinuxCNC will have to be restarted.

Here's the Mesa interface snippet from /etc/network/interfaces, note no DNS nor Gateway as mentioned previously.
Sorry for the delay in answering.