I use Reolink RLC-810 cameras for this purpose, seem to tick your boxes - on their own VLAN isolated away from everything, and I just pull in the streams via RTSP - firmware updates can be uploaded via the camera Web interface. I wouldn't call then "ruggedized", but I live on a fairly remote farm that definitely gets hit hard by the weather, and they have survived just fine.
That exists, but AFAIK the list drops down to nothing again if you add:
1. manufacturers don't actively support genocide (rules out anything involving Dahua, Hikvision, Huawei, as IPVM has described extensively), are allowed in the US (look up the Secure Equipment Act of 2021)
2. has a nice large sensor (the 1/1.8" models are great, but see point 1)
3. supports open source firmware (none of them do AFAIK)
4. reasonably affordable (surprisingly, this part is not the biggest problem)
5. nice-to-have: has an NPU for on-camera analytics (there are cameras with this but mostly from the genocidal manufacturers...)
edit: actually, some of these 6MP Hanwha cameras look promising. Several say they have 1/1.8" sensors. Not cheap though, and no eyeball/turret form factor.
- wired Ethernet (POE is nicer)
- no WiFi nor Zig
- speaks ONVIF
- ruggedized
- 4K
- powerful infrared LEDs
Cannot believe one does not exist.