Pilot here. You always want to keep the engine for the reason of weight and balance and aerodynamical integrity.

They are mounted using shear pins - so if they somehow malfunction so much that they would break the wing, they fall off instead. Self-jettisoning if you want. Here are some examples

https://aviation.stackexchange.com/questions/24935/have-jet-...

I suspect most airframes dont have sufficient spare strength to handle the imbalanced forces of an engine on one wing but not the other during flight.

It's unclear what benefit there would be. On the other hand, instantly changing the balance of the aircraft by jettisoning a large mass from one wing would almost certainly make the aircraft uncontrollable.

An American Airlines DC-10 crashed after takeoff from Chicago in 1979 (?), after one engine separated from the wing. At the time, it was the deadliest crash in the US.

I’m trying to imagine a scenario where that would be beneficial. Maybe uncommanded thrust reverser deployment. Although I think in that case it’s likely to “self-jettison” anyway!

The dangerous bit is the fuel - and that can be cut off from the engine and/or jettisoned.