This a good idea?
This sounds like a fun project that needs some customization, like styling and templating everything to make it look like a blog with federation and comments and not like a Lemmy instance.
Edit: You could also setup GoToSocial for example and set maximum character size to 5000 or so.
This will give you a place to blog and get comments. Readers need a front-end and for them it just looks like a Mastodon account, but you could use styling and template magic to convert the back-end into a nice looking blog front-end.
It’s easy to setup, host, and maintain and runs on fairly low resources.
Lemmy or Piefed? Which is easier to host
Can’t say anything about Piefed, but from what I tried quite some time ago, Lemmy is absurdly annoying to properly set up in an already existing Docker environment with an already existing reverse proxy, because it wants to basically handle everything on it’s own.
It might be actually easier to use another machine or a VM and install Docker there and let Lemmy do whatever it wants to do und just proxy from your main setup to the Lemmy setup.
I gave up.