Try install a web server like Nginx. I think the Raspberry Pi OS is based on Debian, so sudo apt install nginx should work. Then hit the Pi’s address (no port number needed) and it should show a default page.

Phones sometimes will ignore your local DNS (if any) and still use whatever the vendor hardcoded.

For what it’s worth, this is mostly for security reasons - they’re using DNS-over-HTTPS so that the DNS requests are encrypted.

If you’re using the app on the phones, try the website instead?

Is it just Nextcloud having issues? Can you access other services on the Pi from the phones?

Your ps output doesn’t show systemd as running. The only output is the grep command itself.

If you want to play files over SMB, you can just open the SMB mount in the file explorer and double click it. On Windows you can mount it as a network drive (like V: for videos) so even non-technical users understand it. I don’t understand how mpv is easier for that use case.

With systems like Jellyfin and Plex, you can (and should!) turn off transcoding when streaming at home. The only times you should enable transcoding are when:

1. You’re away from home on a slow internet connection (or your home internet has slow upload speed); or
2. You’re streaming to a less powerful device that can’t handle the full bitrate of the video.

Transcoding is very useful, because otherwise you’d need multiple copies of the same movie to handle different environments. Transcoding can dynamically adjust the bitrate based on the connection speed.

Seems like BASIC but with different keywords :D

I like this part of the readme:

How to use

Please don’t.

YouTube only counts a view if it’s longer than 30 seconds, but clients like Newpipe don’t send the tracking data to Google for them to track this.