Is Reddit nuking links to this domain?

Yes. As well as kbin.

We had the same issue over on r/sissy and r/sissies (https://www.reddit.com/r/Sissy/comments/14bwdvm/alternative_to_reddit/)

What we did in our subreddits is using an URL shortener and linking a part of the text to the short URL. That works really well

I read similar stuff by other users, linking to lemmy for replacements of down instances.

I had the same experience. Writing something like lemmynsfw_dot_com so that it isn't recognized as an URL (still) works.