I need Japanese and Chinese, also handwritten for kanji, and the only one that combines both without analytics or internet permission currently is Multiling O [1] but I am hoping for an alternative, because it is only distributed through the Play Store, and I do not use Google services.

Otherwise, open source and on F-Droid there's AnySoftKeyboard [2] and even a build of Mozc [3], this last one unfortunately with internet permission.

[1] https://play.google.com/store/apps/details?id=kl.ime.oh

[2] https://f-droid.org/en/packages/com.menny.android.anysoftkey...

[3] https://f-droid.org/en/packages/org.mozc.android.inputmethod...

"Hacker's Keyboard" on f-droid had a long and venerable history.