I haven’t tried abiword as I didn’t use it “back in the day”, but I might give it a go. I’m also using AppleWorks on my iMac G3 with an identical setup. The G3 is nice because it’s fanless and therefore almost silent, though it has a bit of CRT whine nowadays.
Debian would also work nicely on that g3. Bring both of them up to date!
Rclone supports drop box. It’s more of a 15 minute rtfm task than an Easter weekend. If you are celebrating have a nice Easter.
Of course you can go with an older version of Debian.
Or you can give FreeBSD a spin. Still works nicely on those old machines, including the latest versions! (NetBSD and OpenBSD work too, but they are harder to install and their boot loader is pickier.)
[0] https://www.adelielinux.org/ [1] https://www.youtube.com/watch?v=LLLfCgBu96M