I use pass[1], which has an unofficial Android app[2]. When you select a password in the Android app, it lets you paste it to any text field using normal copy & paste. Clicking the password does the "copy" part of the operation automatically. After a brief timeout, the password is no longer available to be pasted.

[1] - https://www.passwordstore.org/

[2] - https://github.com/zeapo/Android-Password-Store