How do you extend an image and shape it

I have a project that I posted on Github to make this question easier, I have snapshots, and the project, with sample images.

Basically I am downloading the NASA Satelite images of the Sun, NASA decided not to set the focus of the camera to film the whole bloom, bad decision if you ask me, but now my question is how do I fix it, I have tried to mask out the hard lines, that makes the Suns bloom smaller, and I do not like the effect, because it is not natural, and I know I may not be able to achieve this, but I want to get close, and someone started to help me, but due to medical issues, it took me a long time to get back to this, and I may not have if it was not for the fact that my videos look ugly since I got a 4K monitor.

I am trying to make the Suns bloom not have a sharp edge on the right or left, depending on the time of year, but I only want to extend the bloom, and not create a new bloom, and no hard edges, I have thought about a dynamic mask, but have no idea how to implement it, maybe I can make multiple masks, and switch them, or do edge detection and extend the outer edges if they form a hard line.

Any ideas would be helpful, you can answer them here, or as an issue at Github.

Blooming Sun Github Link

Youtube Sun Videos

Thanks