[...] Reddit cut off public access to Pushshift this summer, so Redditmap.social can only use data generated early this year.

From the blog post "How Big is YouTube?" by Ethan Zuckerman.

It really is time to learn to use a more open platform, preferably a Fediverse-compatible one.

Thanks mnalis for posting the fix on the Github issue thread. I had spent time fruitlessly trying the Nextcloud app settings, permissions settings, and other stuff, but nothing had any effect - auto upload would not trigger.

Under Android Settings / User & accounts / Nextcloud / Sync the options File sync was OFF! I toggled it ON and the thing started uploading photos immediately.