This is part rant, part “reference” for anybody else that’s struggling to get their Amcrest IP Camera to work with Home Assistant via ONVIF. Skip to TL;DR for a working Home Assistant config. Briefly, ONVIF is an industry group that maintains a set of standards to allow for interoperability between IP Cameras and related devices from multiple vendors. One set of protocols so your cameras from $vendorA will work with with the recording/analytics software from $vendorB which can then pipe events into software from $vendorC.
Tasmota is an incredibly powerful alternative/open source firmware for the ever popular Espressif family of WiFi equipped microcontrollers. This does not need to be another post espousing it’s many awesome qualities, so just trust me on this; Tasmota is AWESOME. Tasmota supports user configurable rules which are simple commands wired into various device triggers. In short; a device running Tasmota gains some autonomy to react to events without needing to report the event to, and wait for commands from, a remote server.