This was my very unscientific attempt at opening many streams to my Owncast to see if it could support many open streams.

I could. I have 3 qualities, LOW, MED, HIGH (which is a passthrough). Owncast only has to transcode each of these qualities once. Then the only issue you contend with is bandwitdh.

My $8/month VPS from Hetzner was fine on all fronts.

As for bandwidth, Owncast supports S3 buckets and CDNs if someone can go through 20TB/month that Hetzner gives.

I have figured out I can use ffmpeg to open streams and throw them to /dev/null so gonna try that next! Stay tuned!