To be abble to transform gutenberg core block into ACF custom block

gutenberg.js

window.F = window.F || {}; //your custom namespace
//prepare yours transformers
window.F.blocks = {
    transformParagraphToQuestion(attributes) { //the transform name you write un your PHP
        //very ugly, maybe ask to ACF is there is a better option?
        let interval = setInterval(() => { //we wait for the ACF block fields to be ready in the DOM
            //your ACF field key in the block
            //mine is a wysiwyg field, so I look for an iframe, but else you can simply look for the input you want
            let $iframe = document.querySelector('[data-key="field_5e579284bf0a2"] iframe');
            let iframeDoc = null;
            if($iframe && (iframeDoc = ($iframe.contentDocument || $iframe.contentWindow.document)) && iframeDoc.readyState === 'complete') {
                iframeDoc.body.innerHTML = attributes.content; //striptag it if needed
                clearInterval(interval);
            }
        }, 100);
        //the block you want to create
        return wp.blocks.createBlock('acf/question');
    }
};

//then we need to convert the string transformParagraphToQuestion passed by the PHP into a reference to our function
//we use the hook blocks.registerBlockType
wp.hooks.addFilter('blocks.registerBlockType', 'acf', (settings) => {
        if(settings.name.indexOf('acf/') === 0 && settings.transforms) { //we check we are on an ACF field
            ['from', 'to'].forEach(key => {
                let transforms = settings.transforms[key] || null;
                if(!transforms) return;

                transforms.forEach((transform, index) => { //if this block have transforms, we check if the function exists and we replace it
                    if(transform.transform && window.F.blocks[transform.transform]) {
                        settings.transforms[key][index].transform = F.blocks[transform.transform];
                    }
                })
            });
        }

        return settings;
    }
);

//Et voilà

register-block.php

$block = [];//@see https://www.advancedcustomfields.com/resources/acf_register_block_type/
$block['transforms'] = [
    'from' => [[
        'type' => "block",
        'isMultiBlock'=> false,
        'blocks'=> ["core/paragraph", 'core/heading'],
        'transform' => "transformParagraphToQuestion"
    ]],
];
acf_register_block($block);