Errors displaying only with the Acorn v2.0.0-beta.4

I’ve been struggling for a while with the white error page whenever php runs into any kind of an error.
Using latest build - with the bud.
Tried all latest acorn versions (beta8,7,6,5) and finally there comes the 4th one which is working.
composer.json:

{
  "name": "roots/sage",
  "type": "wordpress-theme",
  "license": "MIT",
  "description": "WordPress starter theme with a modern development workflow",
  "homepage": "https://roots.io/sage/",
  "authors": [
    {
      "name": "Ben Word",
      "email": "ben@benword.com",
      "homepage": "https://github.com/retlehs"
    },
    {
      "name": "Scott Walkinshaw",
      "email": "scott.walkinshaw@gmail.com",
      "homepage": "https://github.com/swalkinshaw"
    },
    {
      "name": "QWp6t",
      "email": "hi@qwp6t.me",
      "homepage": "https://github.com/qwp6t"
    },
    {
      "name": "Brandon Nifong",
      "email": "brandon@tendency.me",
      "homepage": "https://github.com/log1x"
    }
  ],
  "keywords": [
    "wordpress"
  ],
  "support": {
    "issues": "https://github.com/roots/sage/issues",
    "forum": "https://discourse.roots.io/"
  },
  "autoload": {
    "psr-4": {
      "App\\": "app/"
    }
  },
  "require": {
    "php": "^7.4|^8.0",
    "roots/acorn": "v2.0.0-beta.4"
  },
  "require-dev": {
    "filp/whoops": "^2.12",
    "squizlabs/php_codesniffer": "^3.6"
  },
  "suggest": {
    "log1x/sage-directives": "A collection of useful Blade directives for WordPress and Sage (^1.0).",
    "log1x/sage-svg": "A useful SVG directive for inlining SVG's within Blade views (^1.0)."
  },
  "config": {
    "optimize-autoloader": true,
    "preferred-install": "dist",
    "sort-packages": true
  },
  "minimum-stability": "dev",
  "prefer-stable": true,
  "scripts": {
    "lint": [
      "phpcs --extensions=php --standard=PSR12 app"
    ],
    "post-autoload-dump": [
      "Roots\\Acorn\\ComposerScripts::postAutoloadDump"
    ]
  },
  "extra": {
    "acorn": {
      "providers": [
        "App\\Providers\\ThemeServiceProvider"
      ]
    }
  }
}

Well fixing errors caused by insufficient permissions leads me to:

Class 'Roots\Acorn\Providers\AcornServiceProvider' not found

Any ideas?
edited:
Switched back to acorn beta-8, still getting the white page with no errors.

Are you just trying to get errors to display in your development environment?