You could at least try to run wp COMMAND --debug to see what this will give you.
I once got this after I manually copied a preprocessed wp-config.php in place to be used inside a Docker container. Suddenly all commands stopped working, silently. The container returned me a 255. With --debug I could identify at which point exactly the commands stopped working and identified that it must have been the wp-config.php.
In the end I fixed it by generating the config with wp config create and suddenly WP-CLI started working again. Would be interesting to know if your error disappears as soon as you remove your wp-config.php. WP-CLI then should tell you that there’s no config existent and might suggest using wp config create to create one.