As usual Weasel has the info you need. To back him up: I've made several trips to Amsterdam in the last few years. I smoked heavily every time - in as many coffee shops as I had time to visit, in Vondelpark (discretely), and in my hotel room (blowing smoke out the window). There are fewer, but still plenty of coffee shops near Centraal, and they can get crowded. Search "coffee shop" on Google Maps and it will pinpoint many shops on the map and give reviews. The further from Centraal, the more chill they are.
Check this out:
https://www.google.com/maps/search/coffee+shop/@52.3643444,4.8764919,14zJust don't ask for weed at the Starbucks that for some reason also shows up in the results.
I've never been carded or hassled, although I have heard that may happen in some border towns that don't want weed tourism. The biggest change from earlier years is that, due to new limits about the quantities of gear that coffee shops are allowed to keep on hand, they are often sold out of some of their menu items.
Many years ago (pre-2001), once when returning from Amsterdam I was searched on re-entering the USA (and they didn't find it). Although I haven't had any other non-routine interactions with TSA, considering the heightened airport security and also the ubiquity of high-grade weed in the US, these days it would be foolish to try to fly with any.