block editor – Use Twenty Twenty-One Theme for Column Layout Homepage?

I’m coming back to WordPress after a while doing other things and wondering if my approach is “old school” and if things have changed with Twenty Twenty-One / WordPress 5.x. / Gutenberg.

I’m about to create a basic flex column-based layout for the homepage of a site. It basically looks like this on Desktop:

Homepage Column Design

In the past, I would have made a specific page template for that page in a child theme then used CSS Media queries to modify for different screen sizes/mobile experience etc.

But with Gutenberg/Twenty Twenty-One, is using a page template still the right approach? Or is there a more up-to-date approach? I see Twenty Twenty-One doesn’t even provide alternative page templates as part of the theme.

And, assuming I didn’t want to add a third-party theme, could/should a layout like the above be created in my own child theme of Twenty Twenty-One?

Back to basics here… Thanks for any help!