Zandronum

I think zcajun is but that's ancient. Bots are available as smart on any platform. And there's a port that attempts to solve each level.

The Zandronum bots are probably the smartest around, not counting AutoDoom. Not like that's saying much with the only competition being some 100% broken bots on GZDoom, and ZDaemon also using the ancient ZCajun bots but very marginally improved, though.