Using Bluetooth Speaker

I know, this was asked before, but like a lot of other people i have also some problems while using volumio with a bluetooth speaker.

Well, i used the bluetooth manager plugin: https://volumio.org/forum/bluetooth-speaker-plugin-t7432-20.html
I installed the ui.zip, overwrite some files and after that i tried two different things:
First: Put the bluetooth_controller.zip in a direcotry, unzip it and installed it with “volumio plugin install”. Did not work.
Second: Go to volumio.local UI > Plugins > Update Plugins > Drag and Drop “bluetooth_controller.zip”. Did not work.

What do i mean with “did not work”? This: https://imgur.com/a/ToO4wsn

bluetooth_controller Plugin
This plugin is failing to start. Please install updated version, or contact plugin developer

The error message appears, when i also try to deinstall the plugin. I have to use SFTP/SSH and delete the folder by myself.
After that i tried something different with the bluetoothctl command. I scanned for my bluetooth speaker, trust it, connect to it and the connection is working (my speaker just made the typical “connection is successful”-sound). I tried to play some music -> no sound.

So, what can i do now? Is there another bluetooth-manager plugin?