[Question]
As of main, it looked to currentNode.body.type !== "ArrowFunctionExpression" || args.expandLastArg reading just rec() in printArrowFunction().
Do the difference cause a problem?

Though it doesn't cause any problem as far as I tried, I'm not sure about it because I'm not familiar with expandLastArg.
Example of input I tried:

fooooooooooooooooooooooo(action => a => b => 
  (dispatch123456789098765432123451234567789(action), 1, 2)
);

Do the difference cause a problem?

I also worried about it, and it may cause problem, but I forgot about it...

Related logic here

We need check that.

My idea is get things out of rec(), so we don't need pass many arguments around.

As my first impression, removing || args.expandLastArg int rec() looked to make sense.
But it will change some results, and previous format looks slightly better.
I'm still investigating.

- request.get(
-   "https://preview-9992--prettier.netlify.app",
-   (head) =>
-     (body) =>
-     (modyLoremIpsumDolorAbstractProviderFactoryServiceModule) => {
-       console.log(head, body);
-     },
- );
+ request.get("https://preview-9992--prettier.netlify.app", (head) =>
+   (body) =>
+   (modyLoremIpsumDolorAbstractProviderFactoryServiceModule) => {
+     console.log(head, body);
+   });

This yields same results regardless of || args.expandLastArg. So expandLastArg looks to work.

request.get("https://preview-9992--prettier.netlify.app", (head) => (body) => {
  console.log(head, body);
})

I read the code again, when expandLastArg is true. functionBody can be an ArrowFunctionExpression, and functionBody decides how the body should be printed. Can't find a case to test. 98c36c2 (#14633) should restore the old behavior, I think.

The following code can make functionBody be an ArrowFunctionExpression and effect shouldBreakChain

a("", "", ({}) => () => {
  a;
});

• last argument is ArrrowFunctionExpression satisfies couldExpandArg
• first two arguments satisfies args.length !== 2 in shouldExpandLastArg
• first two arguments is very simple so they will pass headArgs.some(willBreak) in printCallArguments
• the function parameter is not Identifier, so it effect shouldBreakChain

Finally find a case formats differently....

a("", "", ({}) => () => (a ? b : c));