Retrofit headphones to Bluetooth headphones?

I have studio headphones (over-ear) with detachable cables. Is it possible to retrofit it to wireless headphones / Bluetooth headphones, so you can still use them with a cable? I've seen that there are adapters, what exactly can you recommend me there, or What should I pay attention to?

The adapter should not be too big, because that bothers my neck more.

Would the headphones especially with my e-piano, my laptop and my cell phone want to connect.

Thanks in advance and I wish you a Merry Christmas (if you celebrate) and happy holidays!

I'm a lot, but whether it's financially worth it, that's the question. A new purchase would certainly be cheaper