Error in creating/editing category (Joomla 4 fresh installation)

Having some issue in upgrade site, I tested the same in new fresh Jh installation, but the error is the same: when trying to edit or add a Category, I get this error:

An error has occurred.0 Table Category not supported. File not found.

No other plugin/theme/extension installed, only a fresh installation + FC installed (got from latest Github master source: FC Installed Version     4.0-b1)

And randomly navigating FC backend I also get this PHP error (disappearing when refreshing the same backend url):

Exception {#17 #message: "Failed to start application" #code: 500 #file: "/home/test/public_html/libraries/src/Factory.php" #line: 138 trace: { /home/test/public_html/libraries/src/Factory.php:138 { Joomla\CMS\Factory::getApplication() › { › \tthrow new \Exception('Failed to start application', 500); › } } /home/test/public_html/components/com_flexicontent/tasks/estorage.php:46 { …} /home/test/public_html/components/com_flexicontent/tasks/estorage.php:23 { …} } }

Sysinfos:

• PHP Built On     Linux vps01 3.10.0-1160.45.1.el7.x86_64 #1 SMP Wed Oct 13 17:20:51 UTC 2021 x86_64
• Database Type     mysql
• Database Version     10.1.48-MariaDB
• Database Collation     latin1_swedish_ci
• Database Connection Collation     utf8mb4_unicode_ci
• Database Connection Encryption     None
• Database Server Supports Connection Encryption     No
• PHP Version     7.4.25
• Web Server     Apache/2.4.6
• WebServer to PHP Interface     cgi-fcgi
• Joomla! Version     Joomla! 4.0.4 Stable [ Furaha ] 24-October-2021 19:25 GMT
• User Agent     Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:94.0) Gecko/20100101 Firefox/94.0

I would like to get it fixed & working, I need to upgrade a site having ~2000 articoles and ~200 categories...

Thanks

Felxicontent isn't j4 compatbile for now beta is coming but need time please