Same. Since March of this year. My workaround is to stream to Glimesh.tv and then rebroadcast to Twitch using https://airca.st.
It truly is a Converge issue only, as the problem persists on all my streaming devices regardless of operating system, streaming software, bitrate, etc. When I switch to my Globe backup internet, it's fine.
I've been trying to have it fixed with Converge ever since MARCH. They hardly ever reply to emails anymore, and when they do it's always the usual "restart modern, send screenshots of ping & traceroute" which is always the same result. I did manage to get a replacement modem one time but the problem didn't go away.
A couple times some technicians did visit, both times they said that this problem has been reported before and that in a couple situations it was fixed by a "network team" which I've since been trying to get my ticket escalated to. But of course, the last email with details I sent was on June 19, and I've been following up every 2 days since then with no progress.
It seems to be a very selective problem too. A couple other streamer friends of mine who are also on Converge seem to have no issues.
You can actually stream to YouTube without a PC by using https://airca.st/ . But it's multi-streaming, because it takes your twitch stream and pushes it to YouTube, which you can't do as a Twitch affiliate.
Aircast may be able to do this for you. Unlike Restream or similar services, it actually pulls your Twitch stream and then pushes them out to other platforms of your choosing. However, there is a £5 fee for output to more than one platform, but still cheaper than the other restream services out there. There are no free options for this method as of right now.
For a free solution, give https://airca.st a try. I used this before ponying up for Restream.io. Either of these methods will not add strain on your PC or bandwidth, as the rebroadcasting of your stream is handled on the service's end.
You can also use custom ffmpeg output settings to convert OBS's "Start Recording" button into an additional stream button. I did this before finding out about airca.st, and even fell back to it whenever airca.st wasn't working. Downside is it will definitely use more resources and bandwidth, as you are essentially encoding and uploading twice.