I never used Eurail esims, but I can tell you that all national SIM providers in the European Union (wich is not the same with Europe the continent) + Iceland, Norway and Lichtenstein have to provide for free Roaming outside the “home” country in the other EU + EEA states. 

Here in EUR its not AT-T, its mostly as ´brand´ Vodafone or T-mob, Lycamobile is the cheap anywhere low-budget alt. I think it will depend if you only/mostly want to do call (many think that is very old-fashioned now-but its tipical USA-style, we tend to use app/whatsapp much more now) to ´the party´ back home or In EUR. We here know a thing about trains etc, but for this not or hardly-and certainly not for those from USA. IF you oinsist on wanting to know more, go to a broad forum like tripadisor-same Q will have been posted and answered there dozens of times and with the USA mindset taken in.

Can I buy 1 eSIM that works for Netherlands, Belgium, Germany, France, Czechia, Austria, and Switzerland?

Sure. There’s hundreds and hundreds of eSIM providers.

Just check before you buy that it includes Switzerland as some providers only cover EU.

Try this comparison site for a start. There are others. It brings up O2 as one possible provider - they cover EU & Switzerland

https://www.simoptions.com