Google Site: migrate from Google Classic to Google Modern

I've backed up my elaborate Google Classic site and want to migrate my backed-up Classic site to Google Modern. Want assistance from someone who has experience with this migration, which I assume is possible. If it's not possible, I then want to migrate to a different platform like WordPress or SquareSpace.

Here's the site as it appears online now: https://sites.google.com/site/stevesewallcv/