We have all the time in the world.
Wasn't OG X-COM abandonware for a while? I seem to recall it being stupid easy to find a copy out on the interwebs back when I gave it a try over a decade ago.
If that's the case, you can't really put that genie back in the bottle.
It was definitely freely available on Abandonia when I was a kid. I want to say I downloaded it for the first time when I was in middle school, so we're talking maybe 2007/2008. The game weirded me out too much to get into it properly and I was still a dipshit kid so I quit on my first mission and didn't think about the game until a few years later. I think the year I bought my copy was late 2011, because I was still in high school and there was no announcement about the remake yet. I bought it specifically because Abandonia had stopped hosting it.There bound to be a ton of old websites that still host copies of old abdandomware/cracked DOS games.
Point to this yarn is that it was definitely freely available at one point but the copyright on it started getting enforced. In retrospect work was probably underway on the remake and Firaxis was flexing its dick to ensure their copyright was still secure. OpenXcom's reliance on having the original game assets is purely a copyright protection scheme. You shouldn't have any trouble finding a torrent of the game. The assets are so small I was able to email it to some friends awhile back, and I actually considered just straight up attaching it to the OP but I figured that would just invite Kiwi Farms's first legitimate DMCA notice.