Moving without my cats

I have two cats, one is 3 one is 4 and they live with me and my mom. They are really attached to me and to my mom as well. We live in a big house, they have a lot of space to get sunlight, run, a lot of toys, basically everything a cat wants.

I’m going to move next year to a country 30h away from my hometown. Meaning, in the best case scenario, I will only be able to visit once a year and for like two weeks? It’s a very expensive flight and long hours. I’m going to be away for six years.

My mom said she will take care of them. I can’t take the thought of leaving them in the plane alone, so I would have to take both of them up with me, which would still be stressful and incredibly expensive.

Also i’m going to live in the university dorm for at least a year, so I wouldn’t be able to have them there. Besides that, houses in the country I’m going to are usually very small, I could save up and bring them later on but the quality of life would decrease so much.

I have peace of mind that leaving them here is the best for them. But I’m suffering so much, thinking they will be like ten years old when I’m back. I’m so so attached to my babies but I can’t think about me.

I’m trying to get them to spend more time with my mom than with me. One already changed and now she sleeps at my moms bed, and the other is still in mine, hopefully I can make her sleep with my mom as well, so I can be more relaxed that she isn’t spending so much time alone.

Another fear is that my mom is kinda old (60) and she has a lot of health problems. I’m even thinking what if she dies lol My mind is going crazy. I have a brother in our town, hopefully he doesn’t move cities as well, and in case something happens, he can take them until I come back.

Idk, has anyone gone through this? Does it get better overtime or do u just miss them forever.