Yep, the FDroid version doesn't have it. But you will loose notifications into that version.

F-droid does not include Google's ML-Kit that detects the post's language and translates them on-device. There is no communication with Google on translations besides downloading the language model. The F-droid version also does not offer Push Notification because of the dependency on Google's Firebase to send such messages to phones from Amethyst's own push server.

Those are the only differences.

That being said, Android is made by Google. The language we code apps on, the compiler, and the IDE is owned by JetBrains but HEAVILY financed by Google as the only actual user of such language. All libraries to render screens, to work with databases, and any libraries to integrate with the OS are made by Google. So, if you don't trust Google, you might have bigger issues than just Google Play Services. If you really want to get away from Google, I wouldn't use Android at all.