A lot of people do use RedGIFs, but it's paywalled/blocked in some regions. (Full disclaimer: I downvote anything paywalled/region locked, I feel like that belongs on more commercial social networks like Reddit.)

There are ways to post video, but I'm not sure how to do it.

Oh, and traditionally GIF means Graphical Interchange Format, it's a very old format that allowed for animated images. The format does not allow sound. MP4 (MPEG-Layer-4) does allow sound (as it is a video format) and it seems to be accepted on "GIF" sites.

Sorry, I don't know the best way you can do it, but I wanted to help with what I did know.

Catbox.moe directly?

Make sure your videos are small in file size. I always compress mine before upload. There's never any error message stating why the upload failed, but I had the same problem and after experimenting a little I figured out that the videos being too large in size was the issue.

I don't use redgifs or anything like that, I prefer direct uploads.

Well, turns out it will last 3 days, since it's 400 MB, and I don't understand ghost link.

Could always try finding a peertube instance that allows NSFW stuff? Link to search for that, but aside that I can't think of anywhere else aside some of the bigger porn sites like PornHub or XVideos