Hi, I'm Eythana, author of the article. A corpus is currently being built! Lots of Amish are actually okay with audio recordings, and there are tons of formerly Amish who contribute too.
Rose Fisher at Michigan State is creating it. We're both interested and slowly working on familiarizing speakers with the orthographies that do actually exist (BBB is our preferred one). They've just been floating around in niche and/or academic crevices and most people don't know about them. Rose has great info on her site here https://penndutchdialects.org/pennsylvania-dutch-isnt-a-writ...
One thing you learn if you study the Amish or interact with them personally: there is no "Amish generally" or "the Amish usually".
Every Amish congregation makes their own rules. The local deacons vote on changes. Each "Fellowship" of congregations has tenets and rules they require to be "in fellowship" but otherwise don't have control over the individual groups. Splits are often driven by disagreement over the fellowship rules.
There are Amish that own cars but the group might specify that each family may only own one car and it must be model X and of color Y with a specific set of features. Most people are aware of the groups that prohibit cars - requiring use of horse and buggy.
Some Amish allow electricity, but only connected to the barn or only when provided by solar power. Or they might only allow it to the extent required to comply with regulation - for example refrigeration for milk on a dairy farm. Some allow cell phones, but not in the home (you leave it in the barn or a lockbox). Some prohibit them entirely. Some Amish groups allow machinery but apply restrictions that don't allow use of the machinery to end up with one farmer greatly out-producing others. So when a farmer gets old they may allow them to buy a tractor for fieldwork but require it be pulled by horses.
You might also be surprised to learn many Amish experiment with new technology. Often the deacons will appoint a "nerdy" (for lack of a better term) person in the community to use some new thing. They'll evaluate its effects and costs. Then hold a vote on whether to allow it and what the rules will be. Sometime their answer to changes is not "no" but "not yet".
The decisions are nominally driven by a desire to be independent and to avoid negatively affecting family life rather than rejecting technology directly. Most don't allow electricity, cell phones, or internet inside the home because it would lead to people not interacting or connecting with each other. When power tools are allowed they're often pneumatic so they don't need to be tied to the grid and thus dependent upon "the English" - though with Solar and batteries that has rapidly changed.
Most don't allow extensive use of farming machinery because it could lead to your neighbor out-producing you, leading to them getting much richer and having more than you leading to discord in the community. If cars are allowed they may require everyone to buy the same car so there is no jealousy or "keeping up with the Joneses".
Amish are just people so they certainly have assholes and jerks but many are friendly people and if you treat them genuinely they'll repay the favor. They will not be offended that you use a cell phone or drive a car.
Surprising how often things boil down to "they're just people and most people, if treated with respect, will repay in kind".