Linux

I'll throw out another way: to access files from your phone, you can use termux. python -m http.server

Install an FTP server on your phone. Connect to it via an FTP client on your PC. EZPZ.

KDE Connect has been mentioned before. You can supplement this and other tools by using a VPN so that both endpoints can see each other even if the underlying network does not allow this. My preferred solutions are Tailscale (managed, cloud-based) or Headscale (for self-hosting).

Kde connect is great.

snapdrop.net if on the same network

Single file? KDE Connect. A folder? Syncthing

If by wirelessly you mean via Wi-Fi network then one convenient option is qrcp. It generates a QR-code right in your terminal, which you can scan with a phone and send/receive files through a web interface on the URL it provides.

If you want to transfer files regularly, there is another option. Almost every distro has Python installed, and the Python has a "built-in" FTP server. You need to just cd into desired directory and run the command python -m pyftpdlib -w. It will open a FTP server with root in this directory. You then can access it through a file manager, like Material Files for example, and send files and folders back and forth. In Material Files you can save the server address for future use.

I use primitive ftpd on the phone and FileZilla on the PC.

If you want just a replacement for Warpinator, LocalSend is definitely the way to go. I used Warpinator before, and LocalSend is just an overall better version of the same thing imo. Finds other devices instantly, can also send text in addition to files and folders, and is available across platforms.

I use Airdroid! It's free and works very well

I find the easiest approach is to connect to the pc via sftp and use a file explorer that supports it - such as ghost commander.

X-plore on android can give file access via Web frontend in paid Version.

With that you can drag and drop files if that's what you're looking for.

Syncthing is great to periodically sync files between Linux and Android. And you could use it as file transfer service for occasional needs if you just share an empty directory.

samba. share a folder on pc, and on your phone use a file manager that can access smb folders in your local network, then just copy or move from or to that folder. bit of a hassle to set up the first time, but makes things more convenient in the long run.

For secure private transfer use the Warp flatpak in Linux and Worrmhole William in Android.

wifi file explorer pro apk

You should try kde connect

Personally, I prefer LocalSend to KDEConnect.

There might be more modern ways of doing this, but I run "Wifi FTP server" on my phone, with my download directory as its root. Then I use filezilla or whatever to transfer what I need. Trouble free and platform agnostic.

There are some browser based solutions like sharedrop.io and file.pizza. I haven't had the latter work for me though, not sure if it's still functional. They work through WebRTC to discover local candidates for receiving files, the same way that video calling typically finds the best connection.

Security

ShareDrop uses a secure and encrypted peer-to-peer connection to transfer information about the file (its name and size) and file data itself. This means that this data is never transfered through any intermediate server but directly between the sender and recipient devices. To achieve this, ShareDrop uses a technology called WebRTC (Web Real-Time Communication), which is provided natively by browsers. You can read more about WebRTC security here.

Alternatively, Material Files (available in F-Droid) can easily create a local FTP server or connect to a NAS. It's also a pretty good file manager app.

kde connect is my recommendation also

KDE Connect

Syncthing

KDE Connect is da Bomb

can recommend KDEConnect it's working surprisingly robust.

Either Localsend, if you're only interested in that one function, or KDE Connect for the ultimate experience.

KDE Connect is amazing. Also works without KDE.

See localsend on github