Godot nailed it with "the engine you've been waiting for." I did some college projects in OGRE, which just narrowly beat out IrrLicht and, like, Sauerbraten. Choices were rough enough that learning all the deep magic and rolling your own remained a completely reasonable choice.

Now I'm not sure why the fuck anyone's still on Unity. Especially for a game jam - a project started last month and finished next month. (I guess you don't care about financial shenanigans if the game is free.)

This is the slow victory of open source. Why pay money to be told "no?" These companies keep inventing new ways for people to not own software. Like they don't understand the almost-as-good alternatives cost zero dollars, have no contractual obligations, invite stone-soup improvements for everyone, and stand a serious risk of becoming just as good. I don't even know what Blender's competing with, these days. It does not matter.