First of all, take a look here: https://thethemefoundry.com/tutorials/getting-ready-for-wordpress-5-0-theme-bundle/
Just two points: ‘’…to have complete theme compatibility with 5.0 **please install and activate the official Classic Editor plugin for your website.’’ and ‘’ Does my theme support the new Gutenberg editor?
Maybe! You’re welcome to try Gutenberg editor out but it’s not something we’re officially supporting with any of our themes. All our help guides will remain specific to WordPress 4.9 and earlier, and we’re only offer ongoing support for themes when the Classic Editor plugin activated.’’
Personally, I tried Make and being in their mailing list I received an email asking me not to risk with Gutenberg.
Please don’t mind (!) but Make - at least in the free version - is extremely limited compared to other builders.
The goal of Gutenberg is to become a site builder and to replace all page builder plugins. Why is WordPress doing this? Do they want to destroy page builder plugins? No. They want to destroy WIX, Weebly, SquareSpace, and any other CMS competitor. Matt Mullenweg said explicitly that authors and users of page builder plugins are collateral damage.
It is your right to choose between WordPress and ClassicPress, but the Classic Editor is a cluttered way.