To clarify the earlier answer, NGINX with RTMP is a great way to mirror the same stream to multiple destinations, but it would be the same stream, with the same resolution and bitrate.
The custom FFMpeg output option above does let you stream to different destinations with different settings, as you can use streaming and recording output simultaneously, and custom FFMpeg output can be configured as a stream.
Restream also just mirrors the same stream to multiple locations.
A better way than OBS Camera to send output from one instance of OBS to another (either on the same machine or different machines) is to use the NDI plugin.
https://obsproject.com/forum/resources/obs-ndi-newtek-ndi™-integration-into-obs-studio.528/
OBS isn't intended to be used with multiple instances on a single machine, but it is possible.