I'm from a region bordering the palatinate region and I'll absolutely back you up on being able to understand them pretty well. There's an amish guy who sometimes pops up on my TikTok feed, and it's always fascinating to me how the language, while it has obviously drifted away over hundreds of years, is still fairly intelligible for me. The comparison to older people from your local village is pretty apt.
Funny sidenote: The highest rate of foreign migrants into the palatinate region --- where the amish came from --- is now from US citizens
For anyone wondering whether this reflects some strange Amish return migration: almost certainly not. It’s overwhelmingly the result of the enormous US military presence around Ramstein, Landstuhl, and Kaiserslautern. It's also not exactly a recent development.