My experience is like yours. Amazon has been very reliable for me and the few times I’ve had a problem, their phone support people have fixed it.
I think one factor might be what city you are in. I’m in Austin and I think there must be a big warehouse nearby because it’s not that unusual for something I order to show up a few hours later.
I'm about 45 minutes outside a couple of major-ish cities (RDU/triangle area). I pass a goat farm just before my house (it's maybe a 1/3rd of a mile away). We still get most Amazon stuff next day, occasionally same day. I was a bit surprised, but here we are.
I think one factor might be what city you are in. I’m in Austin and I think there must be a big warehouse nearby because it’s not that unusual for something I order to show up a few hours later.
FWIW, I placed exactly 100 orders in 2023.