I bought one of these a few months ago.

https://www.amazon.com/dp/product/B07GFGQL36

And it has been flawless.

It is capable of sending BT audio to two devices at the same time.

You will need another BT receiver to be completely wireless though.

I use a KN320 device like this one.

https://www.amazon.com/dp/B07NPJ31SV

Not even remotely an ideal solution. But it has been working quite well.