How can I wirelessly connect my cell phone and PC to my stereo?

We have a stereo and speakers on the terrace connected to the system. How can I connect my cell phone and my PC (not both at the same time) to play sound.

Bluetooth does not work, the signal does not reach through the windows and walls.

I got the best result by having a virtual audio channel on my Windows Notebook, where everything was played, which was sent to another Windows Notebook via an HTTP server.

Both notebooks were connected to WLAN.

But I also want to be able to control music from my cell phone. Is there a possibility? And if so, which ones?

Would you like your neighbors to share your exquisite taste in music? Just invite them in. Then you can save yourself the effort.

Simply connect an Internet radio receiver to it. Then you can e.g. Use the free DJ software Mixxx https://www.mixxx.org/ to play the music on your laptop. This has a broadcast function. You can then set it up like an internet radio station in the Heinmetzwerk and then enter the IP address in the internet radio receiver.

Can that also be done with a cell phone?

Not that one. But I still have a solution that works with a PC, laptop, tablet and cell phone. Just read through it: https://www.tonspion.de/news/chromecast-audio-wird-eingestellt-die-5-besten-alternativen