Advice needed: design some sort of async task in Laravel as C#

Hi folks, I'm writing here hoping to get some good advices on a potential problem that's concerning me a lot.

I had to implement in the shortest time possible a small web app to manage a couple of simple tasks, but very resource consuming, so I went straight on a standard laravel + livewire + blade + mysql approach.

Basically I got to upload some csv containing lots of users (around 800 each) and then foreach user elaborate the informations and create some docs with PhpOffice/Word and PhpOffice/Spreadsheet.

I'm very concerned for 2 simple reasons:

1. elaboration time and resources consumed
2. elaboration running as a sync task

For the first point, well I confide on the app depolyed as PaaS in cloud and the dynamic increase of resources.

For the second point, well, I'm quite walking in the shadows, I got a better experience with C# and async tasks and I'm wandering what's the best possible design with Laravel to come closer to an async task, in order to run the elaboration in the backend without keeping the frontend hostage of this long and tedious elaboration.

I'm at your complete disposal for further infos.

Kind regards Folks and thank a lot in advance!