I used restream too for one month but found it too costly. In the end I settled with cloudflare as I could point that to every RTMP server without worry and the quality and bandwidth speeds were top notch. Really cheap too at like $5 a month instead of Restream being $15-30!

My want to go solution is to find a github repo with it's own RTMP hosting solution that might work on an old PC or a Raspi4!