[F_r_k]

Can't you just dump the website using wget ?

[davidak]

You can also use this but havn't testet it.

wget -N --recursive --page-requisites --html-extension --convert-links https://example.com/

[nine_k]

The idea is to keep the site inside a CMS, but a different CMS, one that generates (most) pages statically rather than on-the-fly.