Here’s one that you can use over WiFi: List of Apps that fit and function well [Post them here.] - #266 by amarok
There are others I’ve seen or heard about, I believe.
If you set up ssh (secure shell), you could use sftp (secure file transfer protocol) to simply select the L5 in the file browser on your computer(s) to expose files and move them across by WiFi. Simple tutorials here: Tips & Tricks · Wiki · Librem5 / Librem 5 Community Wiki · GitLab
With ssh, you can also log in to the L5 over WiFi via the Terminal on your computer, to run commands on a larger screen. (With your computer’s larger, physical keyboard.)