I’m gonna play devil’s advocate here.
You should play around with it. But I’ve been a Linux server admin for a long time and — this might be unpopular — I think Docker is unimportant for your situation. I use Docker daily at work and I love it. But I didn’t bother with it for my home server. I’ll never need to scale it or deploy anything repeatedly or where I need 100% uptime.
At home, I tend to try out new things and my old docker-compose files are just not that valuable. Docker is amazing at work where I have different use cases but it mostly just adds needless complexity on a home server.
I don’t self-host Nextcloud. I have a cheap cloud instance running it and it’s essentially my off-site backup for important documents. I don’t put just anything up there but I live in New Orleans so I feel like I should assume my home server won’t necessarily be online when I most need insurance documents and shit like that.
https://motherfuckingwebsite.com/ If it’s just text, you can probably make a static HTML website and accomplish your goals. I’m not sure what format it’s in now but Markdown is what I use and then just export to HTML.
If you just want to host epub (or equivalent files), you can still make a static page and link to them with Cloudflare Pages, GitHub.io, or one of many free static page hosting sites.