Late to the party but just another vote for Nextcloud. I used a paid subscription initially but then took the plunge, bought a Pi 4 & SSD for storage then read up & figured out how to self host.
It was my first experience with Linux, I fell over many times but dont give in as after all the hair pulling & teeth grinding it becomes rewarding & even a little "fun" when you get there & then become confident enough to take on & complete further Pi projects.
The Pi can handle Libre Office (synced through Nextcloud, handled on mobile by Collabora Office).
Whilst you're at it, why not sync the notes you'll inevitability make on your self hosting journey through your Nextcloud instance? Try Joplin & do away with Google Docs, Evernote etc into the bargain