[qaq]

Sure you can and if grandma is in good health she might survive 10-15 years wait time for this category. "In Canada, for example, you can't sponsor your grandparents" https://www.canada.ca/en/immigration-refugees-citizenship/se...

[int_19h]

I stand corrected wrt this particular category and Canada. It's not the case for most other countries, though. And it is still the case that more family members are eligible in US than most other places. That US has a lot more family immigration compared to others is also an objective fact.

[qaq]

In UK you can and also in most(all?) EU countries and without 10-15 years wait time.