This is totally selfish. How will I feel after Mom dies if I don't go see her now?

Lucie; I'm so sorry for your loss. I am glad you're okay.

Be at peace.

Update: January 4, 2022. Mom is gone. I'm OK. Thank you for all your help.

To be frank, your Mom is already gone, in much the way we all lose our loved ones with dementia, whether they were sweet, unfailingly kind and good, or whether they were not.
I hope that you will not grieve the loss of your mother with self blame and self condemnation. To think that you could be perfect is somewhat hubris, if you know what I mean. You have a disability. You are not God. And you are harming NO ONE by not going. Not everything in life has a pretty answer somewhere all tied up with a bow. Some things just are what they are. We are human beings with limitations, and we are doing the best we can.
I hope you are in therapy so that you will be able to comb out the ways in which some of your habitual thinking is doing you harm. There can be nothing you could have done to deserve this pain; You are struggling with your feelings of obligation. BAD people DO NOT STRUGGLE with these feelings; they have no empathy.
Please try to be a bit easier on yourself. I know you will have been told these things by others, but it is on you whether you embrace them and move forward or not. I wish you so much the best. My heart goes out to you.

You can easily look at this in a way that makes it 100% OK for you NOT to go to see your mom in this very sad condition. Going will not help her and it certainly will not help you. Your siblings appear to understand how you feel too.

You said "I don't want to see her". There you go. Please don't go. If you need therapy to come to terms with this, do it. Otherwise, make your decision with 100% certainty that you are choosing what you want, it is a valid choice, and it is OK.

I wouldn't go at this point, but, you could arrange a phone call where you do the talking you have thought out in advance. Say what you want and don't expect any kind of lucid or friendly response. Maybe have a picture of her from younger happier times with you when you call. You will have unburdened yourself and made peace with yourself. Both my dying parents had calls from the distant child and we didn't know if they heard anything but those calls were the best we could do and were good for us. We also had great parents.

If you use the services of a therapist, this would probably be a good time to explore your question with that person.

I comfortably visited my mom every single day for over 5 years before she died.

On the night That I was fairly sure she’d be dying, I asked that I not be notified until the next morning.

One of the social workers in her facility tried enthusiastically to make me feel guilty about my decision, but was unsuccessful. I knew my mother, and loved her dearly. I knew that she would not have cared either way if I were or were not with her at “the moment”.

I often think fondly of her and remember her at her best. I never, to this day, feel guilty about any aspect of our relationship.

You can tell her right now, right where you are, that you love her and hope that her passing will be sweet and smooth and peaceful. Do that. You have no reason to hate yourself, nor think you might hate yourself.