I'm not sure what your claim is based on. Epic members including Tim Sweeney and Cliff Bleszinski are among those credited for programming and designing them.
Also, if you're the copyright holder, no amount of contract work would take away from that, so you'd still have every right to not allow your IP to be used.
They may have done engine work. But the actual unreal tournament games were built by Digital Extremes. It is why they have periodically released the UT weapon skins in Warframe.
This is great news! I had to use Internet Archive to download Unreal Tournament 1999 as i lost the disk ages ago and still play online to this day. Epic shut down the UT99 master server browser a year ago, but everyone is playing it using the community patches anyways.