There’s only one kind of book I read on my laptop now- programming books PDFs. To code side by side. That's all. And PDF is better for rendering equations, graphs, code with syntax highlighting, and figures.
I use EPUB for "flat" essays, novels, storybooks, poems, etc. i.e. non-text/non-technical stuff.
And I use my Kindle or my tab always for that.
For the once or twice need of opening EPUBs on my laptop, I just use Okular.
Won't install something via Snap/Flat or compile it for that one-off kinds of use.