This composer stuff is a mess; there’s a mix of versions 6.2 and 6.3 libraries (never mind that current is 7.0) that should not be there. For example:
$ find /var/www/html/ -name 'LocaleAwareInterface.php'
/var/www/html/admin/libraries/Composer/vendor/symfony/translation-contracts/LocaleAwareInterface.php
/var/www/html/admin/libraries/Composer/vendor/symfony/contracts/Translation/LocaleAwareInterface.php
My experience has been that after initial install of framework there’s a conflict between these interfaces, but then when doing a reinstall it works ok? The thing breaks at first and needs to be manually updated and then reinstalled. It seems like a fragile state of affairs, and devs are just painting themselves into a corner by doing things like manually patching vendor code which will make updates even more difficult in the future.