Put a KWTD into your LFG posts for any activity and play a private match with those that join. They should be as close as it gets. I doubt, it is worth the effort to develop actual bots to fill PvP lobbies. Jumps, abilities etc. add much more possibilities to D2 PvP than you can find in other shooters. This means, bots would need much more possible actions to react to them. Too much effort for a very niche request.