Not mentioned before: KDE connect. It doesn't need KDE to work.

I use PlainApp and I'm quite happy with it. As a lot of these kinds of apps, you do need to be on the same network, but thats not really an issue I find.

https://f-droid.org/packages/com.ismartcoding.plain/

https://github.com/localsend/localsend

https://github.com/szimek/sharedrop

https://github.com/schlagmichdoch/pairdrop

https://github.com/spieglt/FlyingCarpet

https://github.com/subins2000/webdrop

There are tons and tons but LocalSend seems to be the crowd favorite. Any reason that wouldn't work for you?

Localsend is great

it's not as convenient but there are several client apps using the wormhole protocol. They generally require devices to be on the same network but you can tether outside of that scenario.

I'm quite fond of LocalSend.

What exactly are you trying to accomplish?

People (mostly those who use Android phones) called Apple selfish for not opening AirDrop to competition. The EU forced them into an open protocol, but Google has selfishly limited it to phones from the last year hoping people will buy new phones for the feature, proving yet again that Google is probably more evil than you give them credit for. At least Apple shit works with Apple shit. The walled garden is indeed a thing, but hey, it works awesome. Like universal clipboard. And how you can just... use your iPhone... on your Mac. And the shit just works. I can cast my Mac to my Apple TV with nearly zero latency. I'd game on it like that... I mean, if Macs didn't suck for gaming.

Anyway, if you just want an open thing where any two phones can send files across a decent distance (like, not seeing each other or through a wall), that's basically not going to happen. What you need is a sort of "town square" application where you can send a file to anyone using the app who is within X metres of you. And that's fine but everyone will have to have the app. Now if you're face to face, it gets a lot easier. I have an iPhone (16 Pro Max) and a Galaxy (S10) and I can easily toss files between them. Be on the same WiFi network, have one as a server, have the other connect to it, download files, it works both ways. Of course, I trust myself on my own FTP server. I may not trust you and you may not trust me. So having something that open is kind of a no go.

If you wanna be a 1337 ha... yeah, I'm not gonna use all the symbols... you can build a Raspberry Pi type thing, a little self contained computer that has a web server on it. It's on the network, you put a QR code on the case that connects people to it, and they can download off of it. You just make the shared folder write protected so they can't upload anything (like a virus). This is pretty easy stuff for someone who knows how. Maybe you attach a 2TB SSD and put some music and movies on it and just let people come take what they want. Sneakernets have been around for decades, but WiFi makes it a bit easier. Of course that's piracy focused, but that's not the only use, just the most easy to explain.

There are options, but they require participation and cooperation. The cool thing about iPhones is, you could just turn AirDrop on and get memes dropped to you. Even with the 10 minute limit, I just turn it on every 10 minutes at conventions. It's still fun. And really, you can just grab any old secondhand iPhone off Swappa or some other kind of site, or a local pawn shop, just make sure it's not account locked or you're buying a paperweight. You can't (easily) steal an iPhone and some people sell them locked just to screw with people. And people are upgrading theirs all the time, you should be able to get an 11, 12, or 13 fairly cheap.