A main sequence star, regardless of its location within a distant galaxy or the Milky Way, maintains stability during this stage of its life cycle due to a balance between two opposing forces: gravity and nuclear fusion.
How to explain
The star's inward gravitational force tries to compress it, while the outward force generated by nuclear fusion, specifically the conversion of hydrogen into helium in its core, generates energy that counteracts gravitational collapse.
This equilibrium maintains the star's stability, preventing it from collapsing further or expanding abruptly. Therefore, as long as the star remains in the main sequence phase, this equilibrium sustains its stability despite being in a distant galaxy.