I second this.
I have a nextcloud instance on pi4 for personal use and love it.
It’s not good for live transcoding of video, but works great for calendars, file sharing, photo sharing and music streaming.
I have a 500 gig SSD for most stuff and a 6TB HDD for backups and archiving.
I use docker compose to map a folder called archive in my instance to the HDD.
Hell yeah! It’ll be super satisfying to give your system a good cleaning and upgrade. Enjoy!