Yeah, OBS is probably your best bet here. I ran into the exact same issue a while back when I had random outages—my YouTube stream just wouldn't auto-resume without manual input. Switching to OBS and tweaking the reconnect delay and retry settings helped make the whole process automatic unless the connection drops for an extended time.
Also, when I was uploading older mobile-recorded clips to stitch into my live recaps, I had a bunch in 3GP that YouTube didn’t like. Ended up using this
https://www.movavi.com/video-converter/3gp-converter.html video converter to reformat them without losing quality. Much easier than dealing with codec warnings.