Apologizes from late reply. I have Raspberry Pi running Syncthing on LAN. I share my music, youtube-dl'd videos, podcasts etc. with my phone and laptops through it. Also sometimes I use it to share other documents, code etc. Works also as nice backup as the PI runs rsync with cron to store Syncthing contents to other HDD also.

Nextcloud runs on Digital Ocean droplet and I upload my photos there from phone, store contacts and share larger files with people. Currently Syncthing and Nextcloud do not communicate in anyway.

And yeah, youtube-dl has been lifesaver to escape that "rabbithole recommendation engine" as you awesomely put :D