Should I cut my mom off?

I’ll try not to make this a super long post, but does anyone else’s mom pick and choose which grand kids lives she wants to be a part of? Or pick and choose which of your siblings she wants to be a mom to? I’m in my 20s and have never had a close relationship with my mother. Really she was never a mom to me, she lost custody of me and my siblings when we were children and never regained custody. We’re all adults now and all have children of our own. I’ve always kept nice with her and tried to put things aside since we’re all grown. I’ve tried to forgive her and just move past it in hopes that maybe she could be a part of my life as an adult and I guess I hoped that maybe since she didn’t be a mom maybe she’d wanna be a grandma at least, and she is to my sisters kids, just not mine or my other siblings kids. She’s even a mom to my sister and present in her life like a mom should be but doesn’t hardly even speak to me or my other siblings. She will literally speak to me once in a blue moon she’ll send a text every couple months and when I respond she never replies. I send pictures of my kids and she doesn’t respond. I ask her all the time to come over to my house and visit my kids and she doesn’t respond or visit. I’m a single mom and I’ve lived alone with my kids for 2 and a half years and she has visited one time and that’s only because my sister stopped by and she was with my sister. And hell I don’t even know where my mom lives so it’s not like I can just pop up and visit her. With my sister though, she keeps regular contact with her like daily, texts her and calls her every day (I’ve NEVER even spoke on the phone with my mother, only on text) but they talk on the phone constantly, she goes to her house and visits her kids ALL the time and is a grandma to them, sometimes multiple days in a row she will visit them. My sister lives 7 short minutes away from me, yet she still has never just swung my to see me or my kids. My mom is on my social medias so I always hope maybe she sees pictures of my kids on there but she doesn’t interact with any photos or posts about them. But every single post and photo my sister puts on her account I see my mom is always the first to comment and interact. At this point I just feel like I’m begging for a relationship that she doesn’t want with me or my kids. And sometimes I wonder why I even question cutting her off because there would be hardly no difference. I already hardly see or speak to her as is so why not just cut it off completely and lose all hope lol I feel like if you were an outsider to her life you’d assume she only has 1 daughter and 4 grandkids when she has multiple other kids and multiple multiple other grandchildren but she is only present in my sisters kids lives. I feel like if I just stop trying and move on then it will save my kids the heartbreak that I feel in the long run. One day instead of it being me as her daughter questioning why she only loves my sister and not me or my kids, it will be my kids as her grandchildren wondering why grandma only loves the other kids and not them. Thankfully my children are still to young at the moment to understand or realize, but eventually they will start noticing and I don’t want them to feel the same way I do. It’s just not fair. Anyone else deal with something like this?