How is that sad for an old machine?

32 bit version of firefox, because it makes a huge difference in low ram devices.

How so? What CPU does she have?

Last time i searched for “lightweight” linux distros (for an old Thnkpad) the ones i saw recommended the most were: TinyCore, Puppy, Porteus, Absolute, antiX, Q4OS, Slax, Sparky, MX.
I saw Bohdi and other Ubuntu-based distros suggested quite a lot as well but my definition of lightweight means under 1GiB usage.
For a DE go with XFCE or some other lightweight DE.

Joplin synched with syncthing (or Synchthing.fork on android).

As a TV for your kitchen?

Syncthing or https://pairdrop.net/

this distribution would need to be able to handle running for weeks on end without a reboot.

Any decent distro then.
Slackware ftw

They were still on Xitter?

Last time they seeked input they ignored it and shoved systemd anyway…

Works everywhere -available as Flatpak

Don’t you mean Works everywhere where Flatpak is available?

I have no access and, it seems, neither does local IT. Yay.

At the moment i’m getting mount error(13): Permission denied at the new vm (where i was attempting to mount).
dmesg has

[ 9254.003440] CIFS: Attempting to mount \\10.10.10.10\dir\\dir2
[ 9254.181314] CIFS: Status code returned 0xc000006d STATUS_LOGON_FAILURE
[ 9254.181333] CIFS: VFS: \\10.10.10.10 Send error in SessSetup = -13
[ 9254.181367] CIFS: VFS: cifs_mount failed w/return code = -13

Attempting to ls the share in the other vm where it was previously working yields Host is down.
(Everyone else can access the share just fine.)

From my searching around for something similar, these showed up the most: TinyCore, Puppy, Porteus, Absolute, antiX (there’s more).