Hi, sorry for the delay, I was in vacation (and apparently, the forum doesn't send email notification? or it's just a setting on my account). Anyway, I collected the diagnostics you asked for before and after starting the array, so you can maybe see more easily what's going on.
I also want to say that I am using macvlan, although maybe I don't need to anymore, I would have to check to be sure. I did set it up as said in the 6.12.4 release notes, but it didn't fix the issue. My friend is also using macvlan.
EDIT: I switched to ipvlan instead and rebooted. When I start the array, I get the exact same issue where NGINX crashes. I created a new diagnostic file from Tailscale.
tailscale_diag_before-array-start.zip
tailscale_diag_after-array-start.zip
tailscale_diat_ipvlan.zip