here's one of many examples ....
The Antennae Galaxies (also known as NGC 4038 and 4039) are a pair of distorted colliding spiral galaxies about 70 million light-years away, in the constellation of Corvus
Although galaxies look like solid objects they are largely empty space and the distances between star systems and other massive objects is huge.
The chances of two very massive stars colliding is really low, but not impossible, if it happened a one-off supernova might result.
The chances of multiple stellar collisions happening continually whilst the galaxies merge is so low that it might as well be zero.