It’s open source, else I wouldn’t recommended it

https://github.com/LANDrop/LANDrop

I used it along with another called Localsend, but the later one gave me a bit of headache and crashed while transferring some large files last time I used it, but still great as an alternative too, and it’s open source as well.

Edit: Actually, you are correct, it seems they did close it! Try localsend instead.

Love LocalSend. Can be a bit finicky but for quick transfers between systems I love it. Use it so my work laptop, Linux gaming PC, and iPhone can easily pass staff around.