MTG Salvation

While I'm in my brewhouse considering how to make Blim, Comedic Genius work in my meta, I wanted to double check how his donate ability worked with cards like act of treason.

If Blim is not currently linked correctly, his textbox reads;
"Whenever Blim deals combat damage to a player, that player gains control of target permanent you control. Then each player loses life and discards cards equal to the number of permanents they control but don't own."

So for my question here, in a theorietical game I temporarily theft a creature with one of many act of treason effects, deal combat damage with with Blim, and then donate the stolen creature.

At end of turn, would the donated creature return to its actual owner? Or is this more along the lines of Bazaar trader antics where Blims ability overwrites the EOT effect of the act of treason, and the person I donated the creature to gets to keep it?

The most recent still existing control change effect determines the controller of a permanent. Overwriting effects don't make the previous ones disappear. Act of Treason's effect ends in the cleanup step, but Blim's effect remains. So the player granted control by Blim will keep control of the permanent. Meaning, yes, Blim works the same as Bazaar Trader in that regard.

Note, that there is no EOT effect on Act of Treason, its effect just ends when its duration expires in the cleanup step.