I don't think the fight would happen, Elon's mom didn't allow it.
It reminds me something that happened some years ago, with a social media that allowed NSFW videos and pictures. I think it was tumblr or maybe I am wrong. Anyways, if I recall correctly they decided to terminate any content which contained pornography and people started to migrate from there.
In the case of threads, I think it is still too early to say, but considering how some media have been attacking Musk this last year, I would not be surprised if Threads ends up having the backing and advertisement support of many in positions of power, in order to damage Musk's ego and wallet.
Myspace was once like that allowing NSFW until social media was used in politics and there goes myspace whacked. Threads will probably be used to censor topics just like what Twitter was before Elon took over. There are powerful people behind Zuckerberg launching to counter Twitter. They wanna grab the attention and not allow people to watch Tucker Carlson on Twitter.
As for this fight to happen, it really might not happen at all. Musk has much to do.
I learnt one of the reasons for the successful creation and launch of Meta's Thread, is due to the fact that Mark hired many of the employees and top executives who worked at Twitter before they got fired, prior to the acquisition by Elon.
These new employees were of course the brains who designed Twitter and still has access to its secrets.
Let's hope this Thread by Meta won't orchestrate or lend voice to political manipulation or become a tool against the users privacy.