Hi, Ruth. I'm a frequent Delta passenger who generally flies from my local airport (GSP = Greenville/Spartanburg, SC) to Atlanta to get to Europe. Here are my strategies:
Going to Europe through Atlanta: I usually like to make sure there is at least one departure from my local airport AFTER my scheduled departure time that will still get me into Atlanta in time to make the connection. With 8-9 flights to Atlanta per day from my airport, that's easy for me to do. I've been delayed at my local airport for mechanical reasons, a general aviation aircraft having its landing gear collapse on the runway when landing, weather, incoming plane with deceased soldier on it who was offloaded before passengers exited the jet. I've even picked up $600 vouchers for volunteering to be bumped.
Returning from Europe through Atlanta: 2 hours is plenty of time if you have only a carry on. If I'm checking a bag, I usually give myself 3 hours. I've waited at baggage claim for an hour for my bag to arrive twice at ATL.
Transfers through AMS: I'm pretty comfortable with a 90-minute transfer time at AMS. The airport has become much more efficient over the last few years. I've passed through AMS on returning to the US 3 times since May (most recently last month). On the return trip, one does have to go through passport control, but the airport utilizes facial recognition to automate the process for EU, US, and some other countries' citizens. Immediately after exiting passport control, passengers are funneled to a single exit where two airport employees randomly (?) select people to go to the right for a security screen, while most go straight ahead without going through security and head on to their connections. For those who remember the old D1/E1 Delta Inquisition gates/areas, these are gone, as are the at-the-gate security scanners (which the D1/E1 Inquisition areas replaced).