Well, have you called her? It sounds like this is a bit out of character for your mum- yet you don’t seem concerned about her at all? You’ve outlined why you are upset/disappointed/feel let down but doesn’t seem to have crossed your mind that there must be a reason your mum is acting unusually for her. You talk a lot about what you want/expected from her, how you are disappointed she isn’t “checking in” on you and prioritising you. It’s all a bit self-centred- I know that sounds harsh but if my mum suddenly started acting out of character I’d be worried, not put out that I wasn’t getting as much attention as I thought I deserved.
I’d guess there is either something going on for her- could be mixed feelings/worry or even excitement about being retired or there might be something else going on (health problem, problem with your father’s health, financial problems, close friend unwell but not wanting it known etc etc). Or you or your husband have offended/upset her without realising it. Or perhaps she is avoiding the issue related to childcare/drop off and pick up because she’s worried about how you’ll react (and you intimated that last time it came up you didn’t respond quite the way you meant to).
Or perhaps she is stepping back to give you the space to work things out for yourself- maybe she feels if she does too much you will just keep relying on her and not get to grips with having 2 children for yourself? I’m not saying she’s right, but that might be her feelings or concerns. For example, you did outline earlier that you felt it would be too difficult to get out the house on time- but these are struggles that lots of parents who don’t have families on hand to help just have to find ways around. I can understand it feels overwhelming and it is tough, I know- but perhaps she feels that if she keeps stepping in that you’ll keep needing/wanting her to provide ongoing childcare and support when she doesn’t want to/doesn’t feel able to do it anymore. Or perhaps she genuinely assumes that as a second time mum you’ll need a lot less support than before and expects that if you need something that you’ll ask, and doesn’t want to get in the way whilst you and your husband are settling in to having the two children, working out your own routines etc.
In short, I think you should concentrate less on what your mum hasn’t done for you, and more on WHY your mum has been behaving out of character. I think you should ask her if she is ok (not in a way that makes it about why she hasn’t been doing things/asking after you- genuinely ask if she is ok). If she says she is fine, then perhaps she’s just letting you get on with it and/or is excited about the changes in her own life. If you need her help then ask, don’t wait around for your mum to be a mind reader- ask!