Jquery no more loading, load-scripts.php not found (404)

When I open my wordpress website admin panel jquery is not working anymore (it worked yesterday and I don’t see what I changed that can explain that).
The first javascript error I have is GET https://mywebsite/wp-admin/load-scripts.php?c=0&load%5B%5D=jquery-core,jquery-migrate,utils,underscore,wp-util,wp-sanitize,wp-a11y,updates,jquery-ui-core,jquery-ui-widget,jquery-ui-mouse,&load%5B%5D=jquery-ui-sortable&ver=5.2.4&__sbCache=0.6882317019003932 net::ERR_ABORTED 404

And if I try to open https://mywebsite/wp-admin/load-scripts.php the page is not found.
However the page exists in /wp-admin on my ftp.

If the file exists how it can’t be found ? If I rename the file into test.php and call mywebsite/wp-admin/test.php it is found.
To be sure it’s not a htaccess I remove it and I have a 502 bad gateway error, maybe it can help ?

I had this problem with a multisite setup. On my secondary site load-scripts.php returned a 404 error.

the following line in wp-config.php fixed it for me:

define( 'CONCATENATE_SCRIPTS', false ); # worked for me

my .htaccess file:

# BEGIN manual WordPress Multisite
# The directives (lines) between `BEGIN WordPress` and `END WordPress` are
# dynamically generated, and should only be modified via WordPress filters.
# Any changes to the directives between these markers will be overwritten.
<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteBase /
    RewriteRule ^index\.php$ - [L]

    # add a trailing slash to /wp-admin
#    RewriteRule ^([_0-9a-zA-Z-]+/)?wp-admin$ $1wp-admin/ [R=301,L]

    RewriteCond %{REQUEST_FILENAME} -f [OR]
    RewriteCond %{REQUEST_FILENAME} -d
    RewriteRule ^ - [L]
    RewriteRule ^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) $2 [L]
    RewriteRule ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
    RewriteRule . index.php [L]
</IfModule>
# END WordPress

my wp-config.php additional settings:

define( 'WP_ALLOW_MULTISITE', true );
define( 'MULTISITE', true );
define( 'SUBDOMAIN_INSTALL', false );
$base="https://wordpress.stackexchange.com/";
define( 'DOMAIN_CURRENT_SITE', 'localhost' );
define( 'PATH_CURRENT_SITE', "https://wordpress.stackexchange.com/" );
define( 'SITE_ID_CURRENT_SITE', 1 );
define( 'BLOG_ID_CURRENT_SITE', 1 );

define('COOKIE_DOMAIN', '');

define( 'ADMIN_COOKIE_PATH', "https://wordpress.stackexchange.com/" );
define( 'COOKIEPATH', "https://wordpress.stackexchange.com/" );
define( 'SITECOOKIEPATH', "https://wordpress.stackexchange.com/" );
define( 'CONCATENATE_SCRIPTS', false );
/* That's all, stop editing! Happy publishing. */