A lemmy user told me that the alternative UIs with “old.” subdomain don’t require JavaScript to log in.
So with that I can just post from my home instance old.feddit.org in Links.
(old.lemmy.world and old.sdf.org also exist, and probably others as well)

Before that, I had tried all available text browsers, Browsh, Carbonyl and Neonmodem, which all failed for different reasons.