Joomla Transfer. You can take a backup. In the old joomla.

Edit your joomla 3 configurationphp file. This is a mass copypaste tool necessary for all joomla. J2xml is an easy to use importexport solution for your joomla 3 powered website.
It creates a site backup that can be restored on any joomla capable server.
With the new joomla. Export your database via phpmyadmin on your linux hosting and import via phpmyadmin on your new windows hosting. Rename the configuration file. Joomla 4 brings a huge upgrade to the cms amazing new features raises the minimum.