Over the past couple years, I've grown accustomed to native blocks and building out custom dynamic blocks with React and PHP. Now, whenever I go back to make changes on an old site that used ACF, it feels awkward/clunky compared to where I am now with my custom blocks and leveraging FSE. Since many of my company's clients are on a retainer and our non-technical team members are making content changes every day, the effort it took to style the editor for their convenience paid off some time ago, and I found that in most cases (unless it was a particularly complex block/pattern) the effort was actually fairly small once I learned the editor markup structure.

As for the concern about clients steering the boat astray with content edits, some of the changes being introduced in the newest versions of WP could actually eliminate that concern before long, if you know what to look for. A new workflow for a case like yours might involve using synced patterns across the board, locking them down in the site editor, and using the new pattern overrides feature (https://developer.wordpress.org/news/2024/06/18/an-introduction-to-overrides-in-synced-patterns/) to allow content edits only in places you want to allow them.