Structure with blocks does does add json in output

Kirby 4 Question❓
7 
$features = $page->features()->yaml(); //might as well use toSTructure here, but doesn't matter
                            $arr = [];
                            $i = 0; foreach ($features as $feature) {
                                $blocks = new Kirby\Cms\Blocks();

                                if (($feature['title'] ?? null) !== null) {
                                    $title  = new Kirby\Cms\Block([
                                        'content' => [
                                            'text'  => (string)markdown($feature['title']),
                                            'level' => 'h2',
                                        ],
                                        'type'    => 'heading',
                                    ]);
                                    $blocks = $blocks->add($title);
                                    
                                }
                                if (($feature['text'] ?? null) !== null) {
                                    $text   = new Kirby\Cms\Block([
                                        'content' => [
                                            'text' => (string)markdown($feature['text']),
                                        ],
                                        'type'    => 'text',
                                    ]);
                                    $blocks = $blocks->add($text);
                                }
                                if (($feature['cover'] ?? null) !== null) {
                                    $arr[$i]['cover'] = $feature['cover'];
                                }
                                $arr[$i]['blocks'] = Data::encode($blocks->toArray(),'json');
                                $i++;
                            }

                            $page->update([
                                'features' => Data::encode($arr, 'yaml'),
                            ]);

another attempt, still no success, my assumption is, that structures with blocks do not work flawless… Getting a text + textarea to update that info inside a structure > block shouldn’t be that hard.

It seems if there’s no structure, then I don’t run into that problem whatsoever.

As mentioned, there were similar problems before… like here: