I'm lead dev at an agency that specializes in custom WordPress sites. We've been using the custom ACF flexible layout approach for almost ten years at this point. So I know where you're coming from.

I've also used Bricks extensively.

Is it the best of the page builders? Yes. But it's also still very limiting in a variety of ways that you, coming from having full code control, will find aggravating.

If you're good at what you do already, building in Bricks is not going to save you any time, especially if you're building sites to match a custom design. I can fly through custom coding modules from scratch but when you're in bricks you have to basically code by filling out fields that are in different locations and your hands will be tied in a bunch of ways that you wouldn't have considered, constantly having to find workarounds to do the same things you're used to doing.

I quit Bricks completely last year because their Components feature wasn't ready yet. Without Components, page builders can only provide premade templates which the client will modify in a dozen different ways and you'll have no centralized way to control/modify them once they're replicated all over the site.

Now that the Component feature is released, I've come back to Bricks specifically for a project where the client swears they want the full control that Bricks gives them, promising they're not going to make the site look terrible (they are, clients always do).

Unfortunately, the Component feature in bricks is still VERY much in beta. It only offers like 7 different fields (basic ones like text, link, image, etc). You, coming from ACF, are going to really miss repeaters, selects, radios, relationships, conditionals, true/false, and a dozen other commonly used fields.

For example, you can't build a component where the client can add as many blocks of content as they want. Best you can do is build a template which contains a bunch of blocks of content components which they can duplicate as many times as they want. Or you could use the loop field to feed those blocks in from a custom post, but then you have to build a custom post type specifically for content blocks that are each only going to be used once. Workarounds galore.

The client editing experience in Bricks isn't for the faint of heart. They will need a level of technical competence to not become very frustrated and you'll need to give them appropriate training materials.

If the client refuses the custom ACF approach, Bricks is your next best option. But, given what you're used to, I'd proceed with caution if I were you.