ACH is Automated Clearing House, which is US-specific and what's used for faster bank-to-bank transfers than wire. They still take up to a day or two to clear. I suspect what you are calling a wire transfer is not actually the same thing as a SWIFT network wire transfer, which is what's used for international transactions. German banks charge the same fees for those: https://wiretransfer.io/deutsche-bank-germany-wire-transfer/
German banks might have arrangements for doing domestic transfers more quickly, and obviously it's instant if the recipient is at the same bank, but I don't know that that's considered a wire transfer anymore. It would be a direct deposit/debit through some other bank-bank system. (In Canada this would be like Interac transfers, or Zelle in the US)
Ah interesting, so the European banks have agreements on how to settle wire transfers quickly, but going outside those SEPA agreements gets you about the same experience as US wire transfers.
That SEPA system seems kind of nice, since in the US it's been up to a bunch of private companies (like PayPal, Visa, and MasterCard) to pick up the slack and enable instant transfers. We've only recently got the Zelle system, which is free and instant, but even that's just run by some corporation that went around making agreements with banks on their own.
Unfortunately, for this sort of international transaction, the only real options are: Credit card companies (via credit or debit), SWIFT wire transfers (slow and expensive), or Crypto (volatile and maybe slow depending on which one).
I've had annoying times trying to purchase parts from a small UK company, since my only option was wire transfer with a $65 fee, or calling them long distance and giving a credit card over the phone at 1am my time)