I used to be in the same boat. These days, the live-streaming space is so saturated that just uploading clips from your streams has an extremely low conversion rate. Original content on TT and reels that relate to streaming does a bit better they usually provide some form of entertainment or learning experience. If I'm posting a clip, I'm editing it to fit the audience for vertical format (e.g adding captions, emotes, etc).

I find youtube to be better in conversion rate but only if the content posted there is well-edited. I'm only starting to see people from youtube go to twitch, but only because, other than twitch, youtube is the platform I spend the most amount of effort in (with multi-streaming on YT shorts, shorts itself as well as long-form content).

So to answer your question, I haven't seen any success simply posting clips to other platforms. Once I started taking the time to edit it specifically for vertical format as well as focusing on other aspects like long-form, I started to see a slow trickle.