In my story, an advanced alien civilization that can travel to other universes has created an infinite energy source, named "an amvelian core". This core resembles a small sphere in appearance (about the size of a baseball) and the aliens can use it to draw unlimited amounts of energy. Apart from that they can convert its energy into any form of matter (regular matter, antimatter, dark matter, even exotic and strange matter!) These aliens have also discovered a way to open up wormholes. According to their discoveries, there are wormholes all around the universe, connecting distant locations and even other universes. The problem is that they are extremely small, too small for even an electron to pass through. That's because gravity is trying to close up the wormholes. However thanks to the help of cosmic strings (string theory) threaded through them, these wormholes can remain open at their miniscule size. These wormholes are practically everywhere, for example, a single mote of dust can contain thousands of wormholes connecting with the far edges of the universe. Through some method, the aliens of my story have found a way to identify the location in witch the wormhole lead to and by adding exotic matter to it they can enlarge the wormhole for enough time, for a person, or a spaceship to pass through.
Now, in their solar system their parent star is slowly dying off (they have a few centuries before it dies). They have managed to keep their planet safe for some time now by "moving" their planet further away from their parent star. Here's a link to a video explaining how this would work: https://youtu.be/YHin6lk4KqU
However, since this can't last forever, the aliens had to came up with a solution. They built large stations orbiting the sun creating a dyson swarm. In some of these stations there are large machines that convert the energy from the amvelian cores into plasma while at the same time firing it out with high speed inside of a wormhole that is connected to the center of the star and is constantly opened thanks to exotic matter being continuously pumped into the wormhole. Through this method the star will never run out of fuel. However, there is a problem. By adding new fuel into the star's core, they ultimately increase its mass thus making it bigger and hotter. So, some of the other stations around the sun are instead used for a form of star lifting, in which they extract matter from the star's surface, convert it into energy and absorbing it into one of the amvelian cores (I probably should have mentioned this earlier, the amvelian core can also be used to absorb unlimited amounts of energy)
Anyways, my question is: is this a viable method to prevent a star from dying? Are there any mistakes i should look out for? Please let me know.