Zend certified PHP/Magento developer

update 2.3.4 > 2.4.x, composer update: composer-root-update-plugin, it could not be found in any version

Hi i am try to update magento from 2.3.4 to 2.4.x.

I am followed those guides:
https://www.codextblog.com/magento-2/upgrade-magento-version-2-3-x-2-4-0/
https://www.mgt-commerce.com/tutorial/how-to-upgrade-magento-2-3-to-2-4/
https://magecomp.com/blog/upgrade-magento-version-from-2-3-to-2-4/

After commands:

composer require magento/composer-root-update-plugin=~1.0 --no-update
composer require magento/product-community-edition=2.4.2 --no-update

on composer update, i got the errors:

[glow_2@hs23 httpdocs]$ composer update
The "magento/inventory-composer-installer" plugin was skipped because it requires a Plugin API version ("^1.1") that does not match your Composer installation ("2.3.0"). You may need to run composer update with the "--no-plugins" option.

Loading composer repositories with package information
Info from https://repo.packagist.org: #StandWithUkraine

Updating dependencies
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - Root composer.json requires magento/composer-root-update-plugin, it could not be found in any version, there may be a typo in the package name.
  Problem 2
    - Root composer.json requires magento/product-community-edition 2.4.x, found magento/product-community-edition[2.3.4] but it does not match the constraint.

Potential causes:
 - A typo in the package name
 - The package is not available in a stable-enough version according to your minimum-stability setting
   see  for more details.
 - It's a private package and you forgot to add a custom repository to find it

Read  for further common problems.

Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.```

What could problem 1 and 2 mean? Has this happened to anyone else?