Using Laravel Queue for other PHP scripts

hello, I have a project which cant be to scale up with cron, the current project is having around 3k users with use of crontab to run every mint and execute functions, and to handle the number of resources need a dedicated server with more than 32GB just to run the cron as for each function, there is a cron file and this cron will execute this function for all users for example posts scheduling need to check every mint and publish these on the giving time so imagine we have 3k users who just try to post on the same day not to mention how the original structure of the custom framework used in this project make things to be improved difficult without doing a rewrite stuff

so I come with 2 solution

1 - is separate the functions to be run on different servers on a private network and connect to DB with remote connection 2 - is using Queue like what we have here in Laravel and use Redis or other custom drivers like RabbitMQ

now for solution 1 it's considered as a temp solution after some time it will reach to limits also and will have issues when the users become more and more than resources will be an issue I have around 7 to 10 functions need to be separate that a 10 servers to configure!!

now for option 2 is more logical also feel better but I face an issue, how to implement it.

at the moment

in my crontab I have to check every mint and run the cron.php file this class is doing a connection to DB get the table for the action required

processFunction {

    $this->schedulePosts();
    $this->emailSending();
    $this->notifications(); 

}

so these functions will be run one by one till they finish.

when I have around 100 user its ok a small VPS with 4gb can run them no issue but when its reach 3k the project need to have 32GB ram and still get delays.

so what I should do for solving this using Laravel Queue package

if the queue package can be migrated to the project, I just need to send the function? for example, $this->schedulePosts(); to queue and let the package do the magic, or I need to separate all functions to be on their own classes and pass them to the queue, or what!!

hope someone has the knowledge to guide me to solve this issue.

Thanks.