Carolyn Hax: Baby’s here, and now they’re expecting grandparental help

During this pregnancy they indicated they may need me to “help out” again and I began asking multiple times for an idea of what that schedule would look like, with no response until just weeks before her return to work, when they informed me I was going to be the primary caretaker, as the other two relatives were not available. She then texted me a schedule for the next four months.
I am thankfully in good health, but I am also 70 and have a dog and a part-time job. They expect me to drive to their home in rush hour three to five times a week to work eight hours a day.
I was speechless that they would think nothing of expecting this.
I really am struggling with how to tell them this is too much.
We have supported them in many other ways financially and emotionally during their marriage but this is way too much. I just can’t seem to be honest about my feelings without feeling guilty for not being a good grandparent.
Confidential: Oh wow no, that guilt has no foundation. The couple’s entitlement is 100 percent out of line.
The best way to say no is … well, “no,” as always. It’s a great word and its two wee letters contain all the justifications you ever need.
But I feel your ache to be “good.” (Even though you are already and would remain so even if you stuck to the two-letter “no.” To be clear.) So the best way for you to say no is to say YES! … only to the thing you’re willing to do. “Yes! I will care for my new grandbaby … X days a week,” instead of five, or “X hours per day,” instead of eight.
Cheekier than their babies, these parents.
Anyway. Expect them to blanch/balk/flip out so that you are prepared to hold firm when they do: “That’s what I can offer. Let me know if you still want me and on what days.”
If this earns you a full blast of their disapproval, then 1. Wow; 2. That’s their problem, even though it’ll feel like yours; and 3. “I was excited to share the caregiving again, but I never realized you had me in mind for all of it indefinitely. I am not prepared to do that.” That’s an optional fleshing out of your position, mind you, and only to help you feel better. It is not owed.
Look to the other two relatives, not the couple, for reassurance. They are “not available” even part time, much less full, so if you’re a bad grandparent (you aren’t, to be clear), then they’re just as bad or worse grandwhatevers themselves (they aren’t, either).
This does raise the specter of their cutting you off from the kids. That would be cruel and unjustified, and you’d be wrong to cave to that fear, but it is a risk to weigh.
I do feel for the parents on some level, since the whole child-care-business model basically got long covid and hasn’t recovered. They’ll struggle to find care. But that’s not license to assume they can drop it all on you.