olepmac Update on this issue
Solved. Weirdly enough, it installed with this syntax error on line 52:
(/var/www/flarum/vendor/fof/links/src/Command/CreateLinkHandler.php)
$link = Link::build(
Arr::get($data, 'attributes.title'),
Arr::get($data, 'attributes.icon'),
Arr::get($data, 'attributes.url'),
Arr::get($data, 'attributes.isInternal'),
Arr::get($data, 'attributes.isNewtab'),
Arr::get($data, 'attributes.visibility'), // out of place comma
);
Just removing the comma after the last item in the array took care of it.
Has anyone encountered the same issue?