Statamic update failure

I'm running version Statamic 3.0.47 and when I try to update to the newest version (3.1.10, Released on 2021-04-23), I get this error:

dyld: Library not loaded: /usr/local/opt/icu4c/lib/libicuio.68.dylib
Referenced from: /usr/local/Cellar/php/8.0.2_1/bin/php
Reason: image not found

I have successfully tried brew uninstall/reinstall and unlink/link of node, but this don't solve the problem.

Another issue (related?) is when I do a php artisan config:cache I get an error:

Configuration cache cleared!

   LogicException 

  Your configuration files are not serializable.

  at vendor/laravel/framework/src/Illuminate/Foundation/Console/ConfigCacheCommand.php:71
     67▕             require $configPath;
     68▕         } catch (Throwable $e) {
     69▕             $this->files->delete($configPath);
     70▕ 
  ➜  71▕             throw new LogicException('Your configuration files are not serializable.', 0, $e);
     72▕         }
     73▕ 
     74▕         $this->info('Configuration cached successfully!');
     75▕     }

  1   bootstrap/cache/config.php:576
      Error::("Call to undefined method Closure::__set_state()")

      +14 vendor frames 
  16  artisan:37
      Illuminate\Foundation\Console\Kernel::handle(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))

Note: I don't have any file by the name bootstrap/cache/config.php and havn't implemented any Clousures, and only external package installed is pecotamic (sitemap generator).

I have been debugging for hours now without any progress, pretty help, thx.